ISSN:0018-019X    

DOI:10.1002/hlca.19720550202

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

ISSN:0018-019X    

DOI:10.1002/hlca.19720550203

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe synthesis of a new class of corticosteroids with rings A and B rearranged to a 10 (5→4)‐abeosystem is reported. New methods are presented for the preparation and hydrolysis of corticosteroid derivatives, side‐chain‐protected by bis‐methylenedioxy groups, used as intermediates in some of the examp

ISSN:0018-019X    

DOI:10.1002/hlca.19720550204

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractA radical‐induced transfer of an entire functional group in steroid derivatives is described: the photolysis of an 11β‐nitrite function initiates the migration of a nitrile group from the 20‐ to the 18‐position. The reaction was used for the synthesis of new 18‐cyano

ISSN:0018-019X    

DOI:10.1002/hlca.19720550205

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractIn thehypoiodite reactionof 20‐hydroxy steroids, 17α‐ and 17β‐iodo androstanes are formed as by‐products by fragmentation of the intermediate alkoxy radicals. The epimeric iodides show antipodal CD.‐ and ORD.‐ curves in accordance with their absolute configuration at the relevant chiral

ISSN:0018-019X    

DOI:10.1002/hlca.19720550206

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractThe crystal structure of 3β‐acetoxy‐17α‐iodo‐Δ5‐androstene (C21H31O2I) has been determined from three‐dimensional X‐ray data and refined to a final reliability index of R = 5.1% for the 2352 observed reflexions. Crystals grown from methylene chloride/methanol are orthorhombic, space group P212121, with cell constants a = 6.430, b = 10.5

ISSN:0018-019X    

DOI:10.1002/hlca.19720550207

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractA side reaction occurring in theWolff‐Kishnerreduction of certain acetylenic aldehydes (as e.g.2or10) is shown to be a synchronous thermal process. The mechanism of this reaction is discussed in terms of the rules of the conservation of orbital symmetr

ISSN:0018-019X    

DOI:10.1002/hlca.19720550208

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

AbstractA new method for the degradation of the thiazolidine ring in penicillins is described. Penicillin V (8a), penicillin G (8b) and 6‐t‐butoxycarbonylaminopenicillanic acid (33) (BOC‐6‐APA) were convertedviatheir acylazides and isocyanates (10and34) into 2,2,2‐trichloroethyl urethanes (11and35). Reductive removal of the trichloroethoxycarbonyl groups in an aqueous medium gave the 3‐hydroxy‐penam‐derivatives13and36. The structure and various reactions of these carbinolamides are discussed in detail. An oxidative radical fragmentation (using lead tetraacylates and light) followed by thermal treatment transformed the 3‐hydroxy‐penam‐derivatives into the N‐formyl‐β‐lactam‐thio‐enolethers27and37in which the formyl group could be replaced by hydrogen. Reactions of the β‐lactam and thio‐enolether functions are described.The BOC‐derivative37can be transformed into the isomeric compound3, an intermediate inWood

ISSN:0018-019X    

DOI:10.1002/hlca.19720550209

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

Abstract‘7‐aminocephalocillanic acid’1, an intermediate for the preparation of new β‐lactam antibiotics was prepared by transforming the β‐lactam carbinol2ato the phosphorane9athrough several steps. Oxydation of9awith DMSO/Ac2O led directly to the cyclized ester11a, which has been converted into1by kn

ISSN:0018-019X    

DOI:10.1002/hlca.19720550210

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY

摘要:

Abstract3‐Isopropyl‐4‐thia‐2,6‐diazabicyclo[3.2.0]heptan‐7‐on (8), a potential intermediate for the synthesis of new β‐lactam antibiotics [5], was prepared from the urethanes7aand9by reduction with zinc/acetic acid. The cyclicSchiffbase10, which constitutes an intermediate in this reaction, was prepared by reduction of9with CrCl2and was further reduced to8with

ISSN:0018-019X    

DOI:10.1002/hlca.19720550211

出版商:WILEY‐VCH Verlag GmbH    

年代:1972

数据来源: WILEY