Convenient Preparation of Cycloalkenyl Boronic Acid Pinacol Esters

Vivek Rauniyar , Huimin Zhai & Dennis G. Hall
Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada

 

The Suzuki–Miyaura cross-coupling of aryl or alkenyl boronic acids and esters is one of the most important reactions in organic synthesis,[1] and it has been tremendously utilized in the synthesis of natural products and bioactive molecules.[2] In this context, the analogous cycloalkenyl boronic acids and esters are also important coupling partners to access novel, polysubstituted alkenes. These boronic esters can, however, be forbiddingly expensive. (For example, the 2007 Aldrich price for 1 g of cyclohexenyl boronic acid pinacol ester is CDN$ 285) In general, cycloalkenyl boronates are accessed by Miyaura borylation of cycloalkenyl triflates or halides (Scheme 1).[3] The sensitive cycloalkenyl triflates are in turn obtained from the parent cycloalkanones using deprotonation and enolate quenching with expensive triflating agents.[4] Herein, we report a very convenient preparation and isolation of various cycloalkenyl boronic esters using the Shapiro reaction[5] of cycloalkylhydrazones and isolation of the corresponding cycloalkenyl boronic acids as their pinacol esters. Aside from one example where the organoboron product was not isolated, this appears to be the first report of preparation of cycloalkenyl boronic acid pinacol esters using a Shapiro protocol.[6]

 

The current methodology provides the requisite cycloalkenyl boronic esters in 65–90% overall yield for a two-step sequence.[7] While working on the modification of the diol scaffold utilized in the 2 SnCl4-catalyzed allylboration of aldehyde substrates (Scheme 2), we noticed that introduction of cycloalkyl groups in the ortho-position of the hydrobenzoin skeleton was crucial for obtaining homoallyl alcohol products in high enantioselectivities.[8] During our optimization efforts to generate various ring sizes on the diol catalyst 2, we required a rapid preparation of the corresponding cycloalkenyl boronic esters. The latter would serve to install various cycloalkyl rings at the ortho-position of the protected hydrobenzoin 1 by a Suzuki–Miyaura cross-coupling process.

 

A general preparation of cycloalkenyl boronic esters had to be economical and efficient. As such, we envisioned a cycloalkenyl anion capture of a boron-containing electrophile. To this end, we explored a
Shapiro reaction of the cycloalkyl hydrazones to generate cycloalkenyl anions. We anticipated that quenching of the generated anions with commercially available isopropoxy pinacol borate would allow for easier handling and for proper purification and characterization of the products as stable pinacol esters.

 

In the event, as shown in Scheme 3, cycloalkylhydrazones 4 were readily obtained as crystalline solids in almost quantitative yields by a simple addition=dehydration reaction with inexpensive hydrazide reagent 5 in refluxing absolute ethanol. The majority of cycloalkyl hydrazone substrates started to precipitate out when the reaction reached completion, after which the reaction mixture was cooled in an ice bath to allow for completion of crystallization. The freshly obtained cycloalkyl hydrazones 4 were suspended in hexanes followed by addition of N,Ntetramethylethylenediamine (TMEDA) (3 ml=mmol of hydrazone) and cooled to 78 C. This mixture was treated with 4 equivalents of n- BuLi, after which dinitrogen was extruded at room temperature during 1 to 2 h.

 

The resulting orange to red-brown solutions containing the corresponding cycloalkenyl anion equivalents were cooled to 78 C and treated with isopropoxypinacol borate 3 (Scheme 3), and the resulting products were easily purified by flash chromatography over silica gel. The resulting cycloalkenyl boronate products 6 are robust and can be stored for weeks without any observable decomposition. Table 1
illustrates the scope of this protocol. The majority of the products were obtained in good to excellent yields, and this chemistry appears to be general for the preparation of various ring sizes of cycloalkenyl
boronic esters from the corresponding cycloalkanones.

CONCLUSION
We have described a two-step sequence that provides easy access to cycloalkenyl boronic esters in good to excellent yields, and this methodology is readily scalable to multigram quantities. The intermediates are robust and can be stored for months without any observable degradation. Accordingly, expensive reagents including palladium catalyst, bis(pinacolato)diboron, and activating agents are avoided. As such, this method should find widespread application in the preparation of cycloalkenylboronic acid pinacol esters and their application in several types of cross-coupling reactions.

 

EXPERIMENTAL
General
All cycloalkanones were purchased from Aldrich or TCI America. TMEDA was purchased from Acros Organics in 2.5-L containers. Unless otherwise noted, all reactions were performed under an argon atmosphere using flame-dried glassware. TMEDA and hexane were distilled over CaH2. Thin-layer chromatography (TLC) was performed on silica-gel 60 F254 plates and were visualized with UV light and KMnO4 stain. NMR spectra were recorded on 300-, 400-, or 500-MHz instruments. The residual solvent protons (1 H) or the solvent carbons (13C H) were used as internal standards. 1 H NMR data are presented as follows: chemical shift in parts per million downfield from tetramethylsilane (multiplicity, coupling constant, integration). The following abbreviations are used in reporting NMR data: s, singlet; br s, broad singlet; d, doublet; t, triplet; q, quartet; qt, quartet of triplets; dd, doublet of doublets; dt, doublet of triplets; AB, AB quartet; m, multiplet. High-resolution mass spectra were recorded by the University of Alberta Mass Spectrometry Services Laboratory using either electron impact (EI) or electrospray (ES) ionization techniques. Infrared spectra and optical rotations were recorded by the University of Alberta Department of Chemistry Spectral Services.

 

Compound 4a
p-Tolylsulfonylhydrazine (90.0 g, 0.48 mol) was added to a 250-mL flask equipped with a magnetic stirbar, and this white solid was suspended in 60 ml of absolute ethanol. Cyclopentanone (40.7 g, 0.48 mol) was added to this suspension, and the reaction mixture was heated to reflux at 100 C. After heating for 20 min, the mixture dissolved, and after another 20 min, a white solid corresponding to the hydrazone started crashing out. After heating for 1 h, the reaction mixture was cooled using an ice-water bath to precipitate out the majority of the hydrazone. The resulting solid was collected by filtration and was washed thoroughly with ice-cold ethanol. Air drying under reduced pressure for 1 h afforded 114 g of the required hydrazone in near quantitative yield as a white solid with identical spectral properties compared to literature.[9]
 

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5-Amino-3-morpholin-4-yl-1h-pyrazole-4-carbonitrile Catalog No.:AA019OCG CAS No.:103184-16-3 MDL No.:MFCD02071509 MF:C8H11N5O MW:193.2058	2,5-Dibromo-4-pyridinylboronic acid Catalog No.:AA007XZD CAS No.:1031843-77-2 MDL No.:MFCD11109338 MF:C5H4BBr2NO2 MW:280.7098
4-Borono-3,5-difluorobenzoic acid Catalog No.:AA0085WF CAS No.:1031857-98-3 MDL No.:MFCD07786257 MF:C7H5BF2O4 MW:201.9200	3-Amino-1-methyl-1h-indazol-6-ol Catalog No.:AA0090VT CAS No.:1031876-62-6 MDL No.:MFCD11847082 MF:C8H9N3O MW:163.1766
(R)-Methyl 3-aminobutanoate Catalog No.:AA008XGU CAS No.:103189-63-5 MDL No.:MFCD08058803 MF:C5H11NO2 MW:117.1463	1H-Indene-1,3(2H)-dione, 2-(4-bromo-3-hydroxy-2-quinolinyl)- Catalog No.:AA01DNP7 CAS No.:10319-14-9 MDL No.:MFCD00071862 MF:C18H10BrNO3 MW:368.1809
Guanylyl(2' 5')adenosine ammonium salt Catalog No.:AA007HUK CAS No.:103192-47-8 MDL No.:MFCD00058654 MF:C20H28N11O11P MW:629.4772	N-1-BENZYL-2-ETHYL-PIPERAZINE Catalog No.:AA008RY7 CAS No.:1031926-99-4 MDL No.:MFCD07367738 MF:C13H20N2 MW:204.3113
4-(Imidazo[1,2-a]pyrazin-2-yl)-1,2,5-oxadiazol-3-amine Catalog No.:AA008TPL CAS No.:1031927-02-2 MDL No.:MFCD11035755 MF:C8H6N6O MW:202.1728	Methyl 2-bromo-5-cyanobenzoate Catalog No.:AA007HUI CAS No.:1031927-03-3 MDL No.:MFCD11035757 MF:C9H6BrNO2 MW:240.0534
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6-Bromo-3-hydroxyisoquinoline Catalog No.:AA008TTI CAS No.:1031927-91-9 MDL No.:MFCD11110423 MF:C9H6BrNO MW:224.0540	2-Bromo-3,3,3-trifluoro-1-(4-methylpiperazin-1-yl)propan-1-one Catalog No.:AA007HUH CAS No.:1031927-96-4 MDL No.:MFCD09997950 MF:C8H12BrF3N2O MW:289.0929
2-Chloro-6-ethoxy-3-phenylquinoline Catalog No.:AA0092YG CAS No.:1031928-18-3 MDL No.:MFCD09998012 MF:C17H14ClNO MW:283.7522	6-Fluoro-2-hydroxy-3-phenylquinoline Catalog No.:AA0085VX CAS No.:1031928-37-6 MDL No.:MFCD09997959 MF:C15H10FNO MW:239.2444
2,8-Bis(trifluoromethyl)-4-vinylquinoline Catalog No.:AA0085VV CAS No.:1031928-53-6 MDL No.:MFCD10703428 MF:C13H7F6N MW:291.1918	3-Bromo-2-fluoro-5-(trifluoromethyl)pyridine Catalog No.:AA003IXM CAS No.:1031929-01-7 MDL No.:MFCD08061304 MF:C6H2BrF4N MW:243.9844
4-Fluoro-2-iodobenzonitrile Catalog No.:AA007XVL CAS No.:1031929-20-0 MDL No.:MFCD09998181 MF:C7H3FIN MW:247.0083	2-Bromo-3-chlorobenzonitrile Catalog No.:AA003GJW CAS No.:1031929-33-5 MDL No.:MFCD10699544 MF:C7H3BrClN MW:216.4624
7-Bromo-3-hydroxyquinoline-4-carboxylic acid Catalog No.:AA0093F3 CAS No.:1031929-53-9 MDL No.:MFCD10703487 MF:C10H6BrNO3 MW:268.0635	7-(3-chlorophenyl)-3H,4H-thieno[3,2-d]pyrimidin-4-one Catalog No.:AA00J0JW CAS No.:1031969-45-5 MDL No.:MFCD16639689 MF:C12H7ClN2OS MW:262.7148
(E)-Hept-5-en-3-yn-1-ol Catalog No.:AA008V98 CAS No.:103197-98-4 MDL No.:MFCD16710299 MF:C7H10O MW:110.1537	4-{[(thiophen-2-yl)methyl]amino}-1,2-dihydroquinazolin-2-one Catalog No.:AA00J0MN CAS No.:1031970-30-5 MDL No.:MFCD14729149 MF:C13H11N3OS MW:257.3109
7-benzyl-2-(4-fluorophenyl)-3H,4H,5H,6H,7H,8H-pyrido[3,4-d]pyrimidin-4-one Catalog No.:AA01BE9X CAS No.:1031970-76-9 MDL No.:MFCD14729816 MF:C20H18FN3O MW:335.3748	7-(3-methylphenyl)-3H,4H-thieno[3,2-d]pyrimidin-4-one Catalog No.:AA00J0PI CAS No.:1031989-23-7 MDL No.:MFCD16639687 MF:C13H10N2OS MW:242.2963
6-fluoro-1-methyl-7-(4-methylpiperidin-1-yl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid Catalog No.:AA00J0K2 CAS No.:1031989-25-9 MDL No.:MFCD14729053 MF:C17H19FN2O3 MW:318.3428	4-Methyl-1-propylpiperidine Catalog No.:AA01FF9O CAS No.:103199-82-2 MDL No.:MFCD00089156 MF:C9H19N MW:141.2539
1-(N-BUTYL)-4-METHYLPIPERIDINE Catalog No.:AA0090K7 CAS No.:103199-83-3 MDL No.:MFCD00089157 MF:C10H21N MW:155.2804	7-benzyl-2-(4-methylphenyl)-5,6,7,8-tetrahydropyrido[3,4-d]pyrimidin-4(3H)-one Catalog No.:AA00J7IW CAS No.:1031990-66-5 MDL No.:MFCD14729817 MF:C21H21N3O MW:331.4109
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4-(2-Methoxyphenoxy)benzoic acid Catalog No.:AA008RVE CAS No.:103203-54-9 MDL No.:MFCD01570262 MF:C14H12O4 MW:244.2427	3-(Allyloxy)benzoic acid Catalog No.:AA0085VB CAS No.:103203-83-4 MDL No.:MFCD00527900 MF:C10H10O3 MW:178.1846
Chroman-6-carboxylic acid Catalog No.:AA0085VA CAS No.:103203-84-5 MDL No.:MFCD30292879 MF:C10H10O3 MW:178.1846	4-methanesulfonyl-2-[(2-methoxyphenyl)formamido]butanoic acid Catalog No.:AA019P8J CAS No.:1032039-85-2 MDL No.:MFCD08691093 MF:C13H17NO6S MW:315.3422
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tert-Butyl 2'-oxo-2',3'-dihydro-1'H-spiro[piperidine-4,4'-quinoline]-1-carboxylate Catalog No.:AA0096ET CAS No.:1032143-13-7 MDL No.:MFCD15530225 MF:C18H24N2O3 MW:316.3948	tert-Butyl 1-oxo-2,3-dihydro- 1H-spiro[isoquinoline-4,4'-piperidine]-1'-carboxylate Catalog No.:AA0095E6 CAS No.:1032143-15-9 MDL No.:MFCD11227133 MF:C18H24N2O3 MW:316.3948
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Isopentyl 2-(3-oxo-2-piperazinyl)acetate Catalog No.:AA01FO7H CAS No.:1032338-42-3 MDL No.:MFCD08700370 MF:C11H20N2O3 MW:228.2881	Dimethyl 2-[(3-{[3-methoxy-1-(methoxycarbonyl)-3-oxopropyl]amino}propyl)amino]succinate Catalog No.:AA01FO8K CAS No.:1032338-61-6 MDL No.: MF:C15H26N2O8 MW:362.3755
tert-Butyl 1-(4-cyanophenyl)cyclobutylcarbamate Catalog No.:AA0085US CAS No.:1032349-97-5 MDL No.:MFCD15071414 MF:C16H20N2O2 MW:272.3422	tert-Butyl 1-(4-bromophenyl)cyclobutylcarbamate Catalog No.:AA008TH6 CAS No.:1032350-06-3 MDL No.:MFCD18072661 MF:C15H20BrNO2 MW:326.2288
8-(4-(1-Aminocyclobutyl)phenyl)-9-phenyl-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3(2h)-one dihydrochloride Catalog No.:AA008TF8 CAS No.:1032350-13-2 MDL No.:MFCD14584463 MF:C25H23Cl2N5O MW:480.3890	3-Methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine Catalog No.:AA008RST CAS No.:1032358-00-1 MDL No.:MFCD07374972 MF:C12H18BNO2 MW:219.0878
3-Quinolinecarboxylicacid, 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(3-oxo-1-piperazinyl)- Catalog No.:AA0085UR CAS No.:103237-52-1 MDL No.:MFCD04973643 MF:C17H16FN3O4 MW:345.3250	GLUTATHIONE DISODIUM SALT OXIDIZED FORM Catalog No.:AA008RGI CAS No.:103239-24-3 MDL No.:MFCD00148894 MF:C20H30N6Na2O12S2 MW:656.5947
(4-methyl-1,2-oxazol-3-yl)methanol Catalog No.:AA01BUUH CAS No.:103245-31-4 MDL No.:MFCD22571686 MF:C5H7NO2 MW:113.1146	3-(2-Chloropyrimidin-4-yl)-1-methylindole Catalog No.:AA003967 CAS No.:1032452-86-0 MDL No.:MFCD26397861 MF:C13H10ClN3 MW:243.6916
5-(2-phenylpropan-2-yl)-1,3,4-thiadiazol-2-amine Catalog No.:AA01AB5A CAS No.:1032463-93-6 MDL No.:MFCD12104390 MF:C11H13N3S MW:219.3060	4-(4-BROMOPHENYL)-2-AZETIDINONE Catalog No.:AA009LY3 CAS No.:103247-89-8 MDL No.:MFCD11849068 MF:C9H8BrNO MW:226.0699
1-{13-nitro-2-oxa-9-azatricyclo[9.4.0.0^{3,8}]pentadeca-1(11),3(8),4,6,12,14-hexaen-9-yl}ethan-1-one Catalog No.:AA00IX10 CAS No.:103248-97-1 MDL No.:MFCD05669955 MF:C15H12N2O4 MW:284.2668	4-Methyl-2-phenylpyrimidine-5-carboxylic acid Catalog No.:AA007HJV CAS No.:103249-79-2 MDL No.:MFCD02682018 MF:C12H10N2O2 MW:214.2200
5-Acetylpyrimidine Catalog No.:AA003CYW CAS No.:10325-70-9 MDL No.:MFCD09038477 MF:C6H6N2O MW:122.1246	methyl 3-{[(tert-butoxy)carbonyl]amino}pentanoate Catalog No.:AA01BVQN CAS No.:1032506-51-6 MDL No.:MFCD08457624 MF:C11H21NO4 MW:231.2887
3-[4-Fluoro-3-(trifluoromethyl)phenyl]benzonitrile Catalog No.:AA0093YG CAS No.:1032506-84-5 MDL No.:MFCD08457045 MF:C14H7F4N MW:265.2057	4'-Fluoro-3'-(trifluoromethyl)-[1,1'-biphenyl]-4-carbaldehyde Catalog No.:AA01BPGS CAS No.:1032506-87-8 MDL No.:MFCD08457041 MF:C14H8F4O MW:268.2063
Methyl 4-(3,4-difluorophenyl)-3-oxobutanoate Catalog No.:AA01F7JT CAS No.:1032506-99-2 MDL No.:MFCD08457118 MF:C11H10F2O3 MW:228.1921	Methyl 4-(3-nitrophenyl)-3-oxobutanoate Catalog No.:AA01F303 CAS No.:1032507-14-4 MDL No.:MFCD08457138 MF:C11H11NO5 MW:237.2087
3-Amino-2-chloro-6-iodopyridine Catalog No.:AA0093I2 CAS No.:1032507-20-2 MDL No.:MFCD11044245 MF:C5H4ClIN2 MW:254.4561	3-Fluoro-2-methylbenzenesulfonamide Catalog No.:AA01B2V3 CAS No.:1032507-33-7 MDL No.:MFCD09800669 MF:C7H8FNO2S MW:189.2073
2-Bromo-4,6-dichlorobenzenesulfonamide Catalog No.:AA01FCFK CAS No.:1032507-43-9 MDL No.:MFCD09800659 MF:C6H4BrCl2NO2S MW:304.9765	4-Bromo-3-chlorobenzenesulfonamide Catalog No.:AA0090XI CAS No.:1032507-45-1 MDL No.:MFCD09800660 MF:C6H5BrClNO2S MW:270.5314
1-(1,1-Difluoroethyl)-2-iodobenzene Catalog No.:AA00977R CAS No.:1032507-55-3 MDL No.:MFCD10000931 MF:C8H7F2I MW:268.0425	(2-Morpholin-2-yl-ethyl)-carbamic acid tert-butyl ester Catalog No.:AA008VHH CAS No.:1032507-63-3 MDL No.:MFCD09701685 MF:C11H22N2O3 MW:230.3040
3-(1,1-difluoroethyl)benzaldehyde Catalog No.:AA0091JT CAS No.:1032527-37-9 MDL No.:MFCD20527725 MF:C9H8F2O MW:170.1560	4-[(1-BOC-Amino)cyclobutyl]phenylboronic acid pinacol ester Catalog No.:AA007HJT CAS No.:1032528-06-5 MDL No.:MFCD18762017 MF:C21H32BNO4 MW:373.2941
2-cyclohexylpropan-1-amine Catalog No.:AA01A7EF CAS No.:103254-49-5 MDL No.:MFCD11590410 MF:C9H19N MW:141.2539	2-((3-Hydroxyadamantan-1-yl)amino)acetic acid Catalog No.:AA0095JC CAS No.:1032564-18-3 MDL No.:MFCD20278233 MF:C12H19NO3 MW:225.2842
2-Amino-N-[2,3-dihydro-7-methoxy-8-[3-(4-morpholinyl)propoxy]imidazo[1,2-c]quinazolin-5-yl]-5-pyrimidinecarboxamide Catalog No.:AA0039IF CAS No.:1032568-63-0 MDL No.:MFCD18633201 MF:C23H28N8O4 MW:480.5196	2,6-Dibromo-3-iodopyridine Catalog No.:AA0090VA CAS No.:1032582-80-1 MDL No.:MFCD13185520 MF:C5H2Br2IN MW:362.7885
ethyl 5-aMino-1H-pyrazole-4-carboxylate Catalog No.:AA0095XH CAS No.:103259-35-4 MDL No.:MFCD00114562 MF:C6H9N3O2 MW:155.1546	5-(chloromethyl)-3,4-dihydro-1H-2-benzopyran Catalog No.:AA01BZYI CAS No.:1032590-02-5 MDL No.:MFCD20637534 MF:C10H11ClO MW:182.6467
Barium chloride dihydrate Catalog No.:AA003NW6 CAS No.:10326-27-9 MDL No.:MFCD00003445 MF:BaCl2O2 MW:240.2318	CADMIUM PERCHLORATE HEXAHYDRATE Catalog No.:AA003OKC CAS No.:10326-28-0 MDL No.:MFCD00150202 MF:CdClH3O5 MW:230.8848
D-Lactic acid Catalog No.:AA003P4R CAS No.:10326-41-7 MDL No.:MFCD00068311 MF:C3H6O3 MW:90.0779	Ethyl tetrahydropyran-4-yl-acetate Catalog No.:AA007HJL CAS No.:103260-44-2 MDL No.:MFCD03788560 MF:C9H16O3 MW:172.2215
4-Methoxy-1H-indole-2-carboxylic acid Catalog No.:AA003LL0 CAS No.:103260-65-7 MDL No.:MFCD02664458 MF:C10H9NO3 MW:191.1834	8-methylindolizine-2-carboxylic acid Catalog No.:AA01BKB1 CAS No.:103261-63-8 MDL No.:MFCD05157591 MF:C10H9NO2 MW:175.1840
Methyl 4-cyano-2-methylbenzoate Catalog No.:AA007XTW CAS No.:103261-67-2 MDL No.:MFCD18399110 MF:C10H9NO2 MW:175.1840	Methyl 5-cyano-2-methylbenzoate Catalog No.:AA0085U6 CAS No.:103261-68-3 MDL No.:MFCD18399111 MF:C10H9NO2 MW:175.1840
Ethyl benzo[d]thiazole-5-carboxylate Catalog No.:AA0091ZH CAS No.:103261-70-7 MDL No.:MFCD13176733 MF:C10H9NO2S MW:207.2490	3-(Piperidin-1-ylmethyl)phenylboronic acid Catalog No.:AA008SRH CAS No.:1032610-59-5 MDL No.:MFCD08060620 MF:C12H18BNO2 MW:219.0878
2,3-Dihydro-1-benzofuran-5-ylmethanol Catalog No.:AA007HJJ CAS No.:103262-35-7 MDL No.:MFCD02169755 MF:C9H10O2 MW:150.1745	(3-hydroxy-4-methylphenyl)acetic acid Catalog No.:AA008ZYK CAS No.:103262-83-5 MDL No.:MFCD05863285 MF:C9H10O3 MW:166.1739
1-Benzyl-1H-1,2,3-triazole-5-carboxylic acid Catalog No.:AA01BA86 CAS No.:103264-49-9 MDL No.:MFCD11557215 MF:C10H9N3O2 MW:203.1974	7-Bromo-4-chloro-5h-pyrrolo[3,2-d]pyrimidine Catalog No.:AA007XTS CAS No.:1032650-41-1 MDL No.:MFCD11518977 MF:C6H3BrClN3 MW:232.4651
Methyl 2-amino-5-cyano-3-methylbenzoate Catalog No.:AA019ERF CAS No.:1032667-87-0 MDL No.:MFCD20697055 MF:C10H10N2O2 MW:190.1986	Ethyl 2-amino-5-bromo-3-methylbenzoate Catalog No.:AA00H9XR CAS No.:1032668-56-6 MDL No.:MFCD12159932 MF:C10H12BrNO2 MW:258.1118
ethyl 2-amino-5-bromo-3-chlorobenzoate Catalog No.:AA01AJE0 CAS No.:1032668-64-6 MDL No.:MFCD12159924 MF:C9H9BrClNO2 MW:278.5303	Cyanine3 NHS ester Catalog No.:AA0097CJ CAS No.:1032678-38-8 MDL No.:MFCD28505569 MF:C34H40ClN3O4 MW:590.1521
Cyanine5 NHS ester Catalog No.:AA0097CK CAS No.:1032678-42-4 MDL No.: MF:C38H47ClN3O4+ MW:645.2505	(R)-tert-Butyl 3-aminoazepane-1-carboxylate Catalog No.:AA0032BR CAS No.:1032684-85-7 MDL No.:MFCD11041391 MF:C11H22N2O2 MW:214.3046
3,5-Dichloro-1h-1,2,4-triazole Catalog No.:AA007HJA CAS No.:10327-87-4 MDL No.:MFCD01421959 MF:C2HCl2N3 MW:137.9554	6-Chloro-3-pyridin-4-yl[1,2,4]triazolo[4,3-b]pyridazine Catalog No.:AA01ARF4 CAS No.:1032705-69-3 MDL No.:MFCD11042741 MF:C10H6ClN5 MW:231.6411
2-Bromo-4-tert-butylaniline Catalog No.:AA007XS2 CAS No.:103273-01-4 MDL No.:MFCD00052693 MF:C10H14BrN MW:228.1289	5-(4-aminophenyl)-5-methylimidazolidine-2,4-dione Catalog No.:AA019MFS CAS No.:103273-09-2 MDL No.:MFCD10686888 MF:C10H11N3O2 MW:205.2132
DECAHYDROAZULEN-2-ONE Catalog No.:AA01DX4O CAS No.:103274-00-6 MDL No.:MFCD24692496 MF:C10H16O MW:152.2334	5-(3-aminophenyl)-5-methylimidazolidine-2,4-dione Catalog No.:AA019U5S CAS No.:103274-15-3 MDL No.:MFCD11505639 MF:C10H11N3O2 MW:205.2132
5-Amino-1-(3-methylphenyl)-1H-1,2,3-triazole-4-carboxamide Catalog No.:AA01AQH3 CAS No.:103274-40-4 MDL No.:MFCD16653073 MF:C10H11N5O MW:217.2272	3-Bromo-4-(tert-butyl)aniline Catalog No.:AA0096KU CAS No.:103275-21-4 MDL No.:MFCD09966047 MF:C10H14BrN MW:228.1289
2-(2-bromo-4,5-dimethoxyphenyl)ethan-1-amine hydrochloride Catalog No.:AA019L34 CAS No.:103275-23-6 MDL No.:MFCD07352307 MF:C10H15BrClNO2 MW:296.5886	N-(2-chlorobenzyl)-2-propanamine hydrochloride Catalog No.:AA00J1L8 CAS No.:103275-31-6 MDL No.:MFCD08559381 MF:C10H15Cl2N MW:220.1388