BOC-L-Glutamic acid

C17H17N02 ethyl N- diphenylmethylene)glycinate 69555-14-2 25.00 1.1411 2 30216 C17H23N06 boc-L-glutamic acid 5-benzylester 13574-13-5 25.00 1.1888 2... 

Azotomycin is anticancer antibiotic produced by Streptomyces ambofaciens. Total sythesis of it from y-benzyl-N-tert-butyloxycarbonyl-L-glutamic acid (y-OBzi-N-Boc-L-Glu) has been accomplished in nine steps. The mixed carbonic anhydride method was chosen for peptide bond formation. Commerically available y-OBzi-N-Boc-L-Glu was esterified with ethereal diazomethane, deprotected with trifluoroacetic acid-methylene chloride (1 1), and converted to hydrochloride y-benzyl-L-glutamic acid a-methyl ester (y-OBzi-L-Glu-a-OMe HCI) by treatment with dry hydrogen chloride in ethyl ether, MP 129°-135°C (dec.) [a]D25= + 13.3° (CHCI3). 

Proteins to be tested were diluted in buffer E (10 mM HEPES-KOH, pH 7.4,100 mM KC1), at five times their final concentration in the assay. Assay volume was 25 qL and assays were performed in 0.5 mL microcentrifuge tubes. Assays used Buffer L (125 mMKCl, 0.5 mMMgCl2, 3.0 mM succinic acid, 3.0 mM glutamic acid, 10 mM HEPES-KOH, pH 7.4, containing 25 qg/mL leupeptin, 25 qg/mL pepstatin, 3 qg/mL aprotinin, 100 mMPMSL, and 10 qM of the caspase inhibitor Boc-Asp-LMK). Protease inhibitors were added immediately to Buffer L prior to its use. 

Carboxyl group protection. The a -esters of aspartic and glutamic acids are formed readily using the DCC method, after the geminal functionalities are sequestered (by reaction with EtiB). The acid can be regenerated under conditions lO.l M BU4NF) that do not affect an N-Boc group. 

The synthesis of the a-methyl ester of N-acetyl-muramyl-L-alanyl-D-glutamic acid (21) 45) and the ot-methyl ester of N-acetylmuramyl-L-alanyl-D-glutamine (22) 47), starts with the preparation of BOC-L-Ala-D-Glu(OBzl) and Z-L-Ala-D-Gln respectively which were esterified by means of diazomethane. 

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