ISSN:0018-019X    

DOI:10.1002/hlca.19920750802

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe reaction of highly alkylated azulenes with dimethyl acetylenedicarboxylate (ADM) in decalin or tetralin at 180–200° yields, beside the expected heptalene‐ and azulene‐1,2‐dicarboxylates, tetracyclic compounds of type‘anti’‐Vand tricyclic compounds of typeE(cf. Schemes 2–4and8–11). The compounds of type ‘anti’‐VrepresentDiels‐Alderadducts of the primary tricyclic intermediatesAwith ADM. In some cases, the tricyclic compounds of typeEalso underwent a consecutiveDiels‐Alderreaction with ADM to yield the tetracyclic compounds of type ‘anti’‐ or ‘syn’‐VI(cf. Schemes2 and8–11). The tricyclic compounds of typeE, namely4and8, reversibly rearrangevia[1,5]‐C shifts to isomeric tricyclic structures (cf.18and19, respectively, inScheme 6) already at temperatures>50°. Photochemically4rearranges to a corresponding tetracyclic compound20viaa di‐π‐methane reaction. The observed heptalene‐ and azulene‐1,2‐dicarboxylates as well as the tetracyclic compounds of type ‘anti’'‐Vare formed from the primary tricyclic intermediatesAviarearrangement (→heptalenedicarboxylates),retro‐Diels‐Alderreaction (→ azulenedicarboxylates), andDiels‐Alderreaction with ADM. The different reaction channels ofAare dependent on the substituents. However, the main reaction channel ofAis itsretro‐Diels‐Alderreaction to the starting materials (azulene and ADM). The highly reversibleDiels‐Alderreaction of ADM to the five‐membered ring of the azulenes is HOMO(azulene)/LUMO(ADM)‐controlled, in contrast to the at 200° irreversible ADM addition to the seven‐membered ring of the azulenes to yield theDiels‐Alderproducts of typeE. This competing reaction must occur on grounds of orbital‐symmetry conservation under SHOMO(azulene)/LUMO(ADM) control (cf. Schemes 2

ISSN:0018-019X    

DOI:10.1002/hlca.19920750803

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe thermal reaction of 7‐isopropyl‐1,3,4‐trimethylazulene (3‐methylguaiazulene;2) with excess dimethyl acetylenedicarboxylate (ADM) in decalin at 200° leads to the formation of the corresponding heptalene‐ (5a/5band6a/6b;cf. Scheme 3) and azulene‐1,2‐dicarboxylates (7and8, respectively). Together with small amounts of a corresponding tetracyclic compound (‘anti’‐13) these compounds are obtainedviarearrangement (→5a/5band6a/6b),retro‐Diels‐Alderreaction (→7and8), andDiels‐Alderreaction with ADM (→ ‘anti’‐13) from the two primary tricyclic intermediates (14and15;cf. Scheme 5) which are formed by site‐selective addition of ADM to the five‐membered ring of2. In a competingDiels‐Alderreaction, ADM is also added to the seven‐membered ring of2, leading to the formation of the tricyclic compounds9and10and of theDiels‐Alderadducts ‘anti’‐11and ‘anti’‐12, respectively of9and of a third tricyclic intermediate16which is at 200° in thermal equilibrium with9and10(cf. Scheme 6). The heptalenedicarboxylates5aand5bas well as6aand6bare interconverting slowly already at ambient temperature (Scheme 4). The thermal reaction of guaiazulene (1) with excess ADM in decalin at 190° leads alongside with the known heptalene‐ (3a) and azulene‐1,2‐dicarboxylates (4;cf. Schemes 2and7) to the formation of six tetracyclic compounds ‘anti’‐17to ‘anti’‐21as well as ‘syn’‐19and small amounts of a 4:1 mixture of the tricyclic tetracarboxylates22and23. The structure of the tetracyclic compounds can be traced back by aretro‐Diels‐Alderreaction to the corresponding structures of tricyclic compounds (24‐‐29;cf. Scheme 8) which are thermally interconverting by [1,5]‐C shifts at 190°. The tricyclic tetracarboxylates22and23, which are slowly equilibrating already at ambient temperature, are formed by thermal addition of ADM to the seven‐membered ring of dimethyl 5‐isopropyl‐3,8‐dimethylazulene‐1,2‐dicarboxylate (7;cf. Scheme 10). Azulene7which is electronically deactivated by the two MeOCO groups at C(1) and C(2) shows no more thermal reactivity in the presence of ADM at the five‐membered ring (cf. Scheme 11). The tricyclic tetracarboxylates22and23react with excess ADM at 200° in a slowDiels‐Alderreaction to form the tetracyclic hexacarboxylates32, ‘anti’‐33, and ‘anti’‐34(cf. Schemes 10–12as well asScheme 13). A structural correlation of the tri‐ and tetracyclic compounds is only feasible if thermal equilibrationvia[1,5]‐C shifts between all six possible tricyclic tetracarboxylates (22, 23, and35–38;cf. Scheme 13) is assumed. The tetracyclic hexacarboxyla

ISSN:0018-019X    

DOI:10.1002/hlca.19920750804

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractAt room temperature or under reflux in MeCN, 3‐amino‐2H‐azirines2and 3,4‐dihydro‐2H‐1,2‐benzothiazin‐3‐one 1,1‐dioxide (4) give 1,2,5‐benzothiadiazonin‐6‐one 1,1‐dioxides5in fair‐to‐good yield (Scheme 2). The structure of this novel type of heterocyclic compounds has been established by X‐ray crystallography of5a(Fig.). A ring expansionviaa zwitterionic intermediate of typeA' is proposed as the reacti

ISSN:0018-019X    

DOI:10.1002/hlca.19920750805

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractFive‐ and Six‐Membered Cyclic Phosphonic Diamides, Thioester‐amides and Spirobi[oxazaphospholes]By reaction of the 1,2‐diaminobenzene derivatives1a–dwith the phosphonoyl dichlorides2a–g, the 1,3‐dihydro‐1,3,2‐benzodiazaphosphol‐2‐ones4a–qare obtained. The phosponoyl dichlorides2a–e, 2g, and2hyield with naphthalene‐1,8‐diamines (5) the diazaphosphinones6a–gunder similar reaction conditions. The thiazaphosphole oxides9a–dare accessible by reaction of the phosphonoyl dichlorides2a–dwith 2‐aminobenzenethiol (7). Unexpectedly, the reaction of the dichlorides2aand2bwith 2‐aminophenol (10) led to the spirobi[

ISSN:0018-019X    

DOI:10.1002/hlca.19920750806

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe cyclopalladation of two different types of aniline derivatives is described: the acetylated anilinesN‐(3‐methylphenyl)acetamide (2a), 3‐(acetylamino)‐4‐chlorobenzoic acid (2c), andN‐(2‐chlorophenyl)acetamide (2d) are cyclometalated easily with palladium(II) acetate and trifluoroacetic acid to yield the corresponding complexes4a, 4c, and4d, respectively, whereas the acetylatedmeta‐toluidineN‐(2‐chloro‐5‐methylphenyl)acetamide (2b) cannot be metalated at the only accessible site between the acetylamino and the methyl group. This aromatic CH bond can be activated, however, with the second type ofmeta‐toluidine derivatives: the 2‐chloro‐5,N‐dimethyl‐N‐nitrosoaniline (3b) readily undergoes cyclopalladation to yield the corresponding PdIIcomplex di‐μ‐trifluoro‐acetato‐bis[3‐chloro‐6‐methyl‐2‐(N‐methyl‐N‐ nitrosoamino)phenyl‐C,NO]dipalladium(II) (5b) containing a five‐membered palladacycle with coordination of Pd

ISSN:0018-019X    

DOI:10.1002/hlca.19920750807

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe synthesis of glycerolipids linked to hydroxamate derivatives designed for two‐dimensional crystallization of aminopeptidase M is reported. The lipid moieties are readily obtained using a convergent pathway. Their structure allows the introduction of a wide variety of ligands of biological interes

ISSN:0018-019X    

DOI:10.1002/hlca.19920750808

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractSyntheses of Phosphonic‐ and Phosphinic Analogues of Pantothenic Acid Ethyl Ester and of the Phosphonic Analogue of PantetheineThe replacement of amino acids in peptides by phosphono‐analogous (aminoalkyl)phosphonic acids1, (2‐aminoethyl)phosphonic acid (2) and substituted derivatives has been an important aspect of peptides research in the last years. In pantothenic acid (3), there is a peptide linkage between (2R)‐2,4‐dihydroxy‐3,3‐dimethylbutyric acid and the amino group of β‐alanine, and in pantetheine (4), there is a second peptide linkage between the β‐alanine and cysteamine. The synthesis of phosphono and phosphino analogues of pantothenic acid ethyl ester, where the β‐alanine is replaced by the diethyl ester of (2‐aminoethyl)phosphonic acid and the ethyl ester of (2‐aminoethyl)methylphosphonic acid, respectively, and the syntheses of the phosphono analogue of pantetheine, where the β‐alanine is replaced by (2‐aminoethyl

ISSN:0018-019X    

DOI:10.1002/hlca.19920750809

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractVicinal deuterium‐induced6Li‐NMR isotope shifts have been found for (D5)phenyllithium. These shifts are to low field, and their magnitude varies from 7 to 19 ppb with different solvents and donor molecules. On the basis of theisotopic fingerprintsobserved in the6Li‐NMR spectra of C6H56Li/C6D56Li mixtures, the aggregation behaviour of phenyllithium under different solvent conditions and in the presence of amines as donor ligands (TMEDA, PMDTA) was studied. Tetramers and dimers are observed in Et2O, dimers as well as momomers in Et2O/TMEDA and in THF, and momomers in THF/PMDTA. The hitherto unidentified species in Et2O/TMEDA was shown to be a mo

ISSN:0018-019X    

DOI:10.1002/hlca.19920750810

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractOptically active 1,3‐O‐disubstituted glycerols were obtained by enantioselective homogeneous hydrogenation of the corresponding 1,3‐O‐disubstituted 1,3‐dihydroxypropan‐2‐ones with different RuII‐binap complexes. The highest enantioselectivities were obtained with dimeric chloro‐ruthenium complexes on the substrates bearing bulky

ISSN:0018-019X    

DOI:10.1002/hlca.19920750811

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY