ISSN:0165-0513    

DOI:10.1002/recl.19811000902

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstract1‐(Alkylthio)cyclopropyl azides ‐ readily accessible from the corresponding chlorides and bromides ‐ are smoothly decomposed at 70°C with nitrogen evolution. The main process is a ring enlargement to 2‐(alkylthio)azetines2, accompanied by cleavage to thiocyanate and alkene. Reaction parameters for the thioazetine formation suggest a two‐step mechanism involving an intermediate cyclopropylnitrene. Ring enlargement can be averted if the alkylthio group contains a double bond. Thus, the allylthiocyclopropyl azide 8 gives a nitrene that can interact not only with the three‐membered ring but also with the double bond, leading to spirocyclic products (15 and 16 in Scheme 1). The photolysis (300 nm) of these azides gives exclusively the fragmentation products thiocyanat

ISSN:0165-0513    

DOI:10.1002/recl.19811000903

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstract2‐Butynedinitrile reacts by (2 + 4)‐cycloaddition with one or two equivalents of 2,3,4,5‐tetramethylfuran to give 1,4,5,6‐tetramethyl‐7‐oxabicyclo[2.2.1]hepta‐2,5‐diene‐2,3‐dicarbonitrile (1) and 1α,4α,4aα, 5β,8β,8aα‐hexahydro‐1,2,3,4,5,6,7,8‐octamethyl‐1,4:5,8‐diepoxy‐naphthalene‐4a,8a‐dicarbonitrile (5), respectively. The presence of aluminium(III) chloride has no effect on the reactions, unlike the corresponding reaction with the analogous thiophene. On irradiation,1is converted into 2,4,6,7‐tetramethyl‐3‐oxatetracyclo[3.2.0.02,7.04,6]heptane‐1,5‐dicarbonitrile (2) in good yield. The structure of5has

ISSN:0165-0513    

DOI:10.1002/recl.19811000904

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe partially protected heptapeptide, Boc—Asp(OtBu)—Ser—Ser‐Thr‐Ser‐Ala‐Ala‐OH, corresponding to the sequence 14‐20 of bovine pancreatic ribonuclease, was prepared by a combination of solid‐phase synthesis using Nα‐(9‐fluorenylmethoxycarbonyl) amino acids and synthesis in solution by the active ester method. T

ISSN:0165-0513    

DOI:10.1002/recl.19811000905

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractA suitably protected thymidine 3′,5′‐bis(4‐morpholinylphosphonate) derivative was converted into a derivative with two different 3′‐ and 5′‐phosp

ISSN:0165-0513    

DOI:10.1002/recl.19811000906

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe synthesis of the oligoribonucleotides AAG (23), AAGAAG (24) and AAGAAGUUG (25), corresponding to fragments of the nucleation region of Tobacco Mosaic Virus RNA, is described. The assemblage of the oligomers23–25was effected using a phosphotriester method which was based on the use of the monofunctional phosphorylating agents 2,2,2‐trichloroethyl 2‐chlorophenyl phosphorochloridate (7) and the analogous 2,2,2‐tribromoethyl 2‐chloro‐4‐tert‐butylphenyl phosphorochloridate (8). The levulinyl function, which was introduced into the monomeric building blocks1(see Scheme 1) by an improved procedure, was used for the protection of the 5′‐hydroxyl group of phosphotriester intermediates. Deblocking of the fully protected oligomers15f, 17gand19hwith fluoride ions, followed by ammonia and acid treatment, afforded the desired derivatives AAG, AAGAAG and AAGAAGUUG, respectiv

ISSN:0165-0513    

DOI:10.1002/recl.19811000907

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractThe 1,3‐dipoles 2,4,6‐trimethylbenzonitrile oxide and benzyl azide react with alkyldicyanamides (1) to give the 3,5‐disubstituted 1,2,4‐oxadiazoles2and the 1,5‐disubstituted tetrazole4, respectively, by (3 + 2)‐cycloaddition. The structure of 4 has been determined by a single crystal X

ISSN:0165-0513    

DOI:10.1002/recl.19811000908

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractAn alternative route to 3‐arylpiperidines is described, thereby circumventing traditional Michael addition of substituted phenylacetonitriles to methyl acrylate. Treatment of (3‐methoxyphenyl)acetonitrile (2) with the THP ether of 3‐bromo‐1‐propanol, followed by chromic acid oxidation and saponification provided 2‐(3‐methoxyphenyl)glutaric acid (6). Treatment of the corresponding anhydride7with alkyl‐ and arylalkylamines provided the imides8a‐c. Replacement of the methoxy group by a benzyloxy group, followed by LiAlH4reduction and a catalytic reduction p

ISSN:0165-0513    

DOI:10.1002/recl.19811000909

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

Abstract1,3‐Diynes HCCCCR′ (1, R′  H or Ph) are converted by cuprates [RCuY]M′ (R  alkyl; Y  Cl, Br or R; M′  Li, MgCl or MgBr) into a mixture of [HC(CuY)C(R)CCR′]M′ (2) and [RCHC(CuY)CCR′]M′ (3). When R is n‐alkyl, adducts2are the major products; adducts3are preferentially formed when R is a branched alkyl. Organoargentates [RAgY]MgCl (R  alkyl, Y  Br or R) convert diynes1selectively into [RCHC(AgY)CCR′]MgCl (6). The latter regiospecific reaction has been used to prepare functionally substituted e

ISSN:0165-0513    

DOI:10.1002/recl.19811000910

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY

摘要:

AbstractOn the basis of studies of the relationship between structure and mass‐spectral fragmentation, deuterium‐substituted cannabinoids and analogues thereof have been prepa

ISSN:0165-0513    

DOI:10.1002/recl.19811000911

出版商:WILEY‐VCH Verlag    

年代:1981

数据来源: WILEY