摘要:

AbstractThe synthesis is reported of the five mononitrofluoranthenes. 1‐Nitrofluoranthene was synthesized in 20% from fluoranthene, 2‐nitrofluoranthene in 24% from 1,2,3,10b‐tetrahydrofluoranthene, 3‐nitrofluoranthene in 13% from fluoranthene and 7‐ and 8‐nitrofluoranthene in 34% from 1,2,3,10b‐tetrahydrofluoranthene. The pure nitrofluoranthenes were converted into their nitroso and amino analogues. The nitrosopyrenes were also synthesized. Characterisation of each compound

ISSN:0165-0513    

DOI:10.1002/recl.19921110701

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe cycloadditions of 3‐(p‐toluenesulfonyl)‐2‐propenal with cyclopentadiene, 1,3‐cyclo‐hexadiene, 1‐methoxy‐1,3‐cyclohexadiene, 1‐(trimethylsilyloxy)‐1,3‐butadiene, or 1,3‐diphenyliso‐benzofuran have been easily carried out at room temperature in the absence of catalyst. In contrast, furan has led to a Michael‐type addition. The basic elimination of the sulfonyl moiety of a cyclo‐adduct has shown that this dienophile is a s

ISSN:0165-0513    

DOI:10.1002/recl.19921110702

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractAn efficient cleavage‐isopropylidenation reaction of sucrose, catalyzed by iodine, is described. Related D‐fructofuranosyl‐containing oligosaccharides, some common disaccharides and their individual monosaccharide units were treated in a similar manner to yield isopropylidenated monosaccharide derivatives. The reaction conditions are particularly mild and selective. Some mechanistic aspects of the procedure are also disc

ISSN:0165-0513    

DOI:10.1002/recl.19921110703

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractMolecular receptors for organic molecules are described in which calix[4]arene is used as amolecular platformrather than for itscavity. This is illustrated by the synthesis of a receptor for barbiturates, a calix[4]arene in a cone conformation containing two diaminotriazine moieties at the upper rim. This receptor(9)forms a molecular cleft in which phenobarbital complexes by hydrogen bonding both triazine rings. The association constantKis 520 M1, when the self‐association of the barbiturate is taken into accoun

ISSN:0165-0513    

DOI:10.1002/recl.19921110704

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractIn order to develop an expedient synthetic route to γ‐oxo‐α‐aminocarboxamides, five different α‐(alkoxycarbonyl)amino‐α‐methoxyacetamides were subjected to borontrifluoride‐etherate‐mediated reactions with one silyl ketene acetal and four silyl enol ethers. Reactions of primary and secondary amides did not lead to the desired CCbond formation. Reactions of the tertiaryN,N‐dimethylamide gave the expected γ‐oxo‐α‐aminocarboxamides. The reaction of anN‐methoxy‐N‐trimethylsilylcarboxamide with the ketene acetal also proceeded normally. However, the initial products of the latter amide with silyl enol ethers reacted further by cyclization, respectively, to give a cyclicN‐ methoxy‐N‐acyliminium intermediate. Depending on structural features of the enol ether used, this iminium intermediate suffered either proton loss and isomerization to give protected 3‐amino‐1‐methoxy‐δ3‐pyrrolin‐2‐ones, or underwent a second coupling with the eno

ISSN:0165-0513    

DOI:10.1002/recl.19921110705

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractFully benzylated or benzoylated phenyl selenoglycosides can be activated by the promoters iodonium di‐sym‐collidine perchlorate (IDCP) orN‐iodosuccinimide and catalytic triflic acid (NIS/TfOHcat.). The potential of the iodonium ion‐mediated glycosidations of phenyl selenoglycosides is illustrated in the chemoselective synthesis of 1,2‐cis‐or 1,2‐trans‐linke

ISSN:0165-0513    

DOI:10.1002/recl.19921110706

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe phosphonate ethyl 6‐(diethylphosphono)‐2E,4E‐hexadienoic acid is a suitable synthon for the highly stereoselective preparation of 2E,4E,6E,11Z‐octadecatetraenoic acid and its 2E,4E,6E

ISSN:0165-0513    

DOI:10.1002/recl.19921110707

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19921110709

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19921110711

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY