摘要:

Organic Phosphorus Compounds. XVI. On the Chemistry of the Isocyanatophosphoric Acid Diethyl EsterA one‐pot procedure for preparing ureidophosphoric acid dialkyl esters2from POCl3, urea, and alcohols via ureidophosphoric acid dichloride1was worked out.2(REt) was used as starting material for isocyanatophosphoric acid diethyl ester (4, REt), the reaction of which with anilines and various other primary amines afforded a series of new N'‐substituted ureidophosphoric acid diethyl este

ISSN:0021-8383    

DOI:10.1002/prac.19903320403

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractBoth 2 and 4 halogenated 3‐aminopyridines react thermally with α‐mercapto esters and amides to afford pyrido[2,3‐b] and pyrido[4,3‐b][1,4]thiazinones. N‐alkylation and oxidation of the products were in

ISSN:0021-8383    

DOI:10.1002/prac.19903320404

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

Substituted 2‐Amino‐thiazoles from α‐Thiocyanato‐acetophenones and Dialkylaminesα‐Thiocyanato‐acetophenones1react with dialkylammonium salts of weak acids (acetates, propionates, benzoates) to give 2‐dialkylamino‐4‐aryl‐thiazoles4. As reaction medium aliphatic alcohols (methanol, ethanol), dipolar‐aprotic solvents (acetonitrile, dimethylformamide, dimethyl sulphoxide) or chlorinated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) can be used. In comparison to known methods for the preparation of the thiazoles4the synthesis via α‐thiocyanato‐acetophenones1has the advantage of the simpler accessible starting compounds. – I.r., u.v., n.m.r. and mass spectroscopic data

ISSN:0021-8383    

DOI:10.1002/prac.19903320405

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

13C‐N.M.R. Spektroscopical Studies on Simply Substituted Flavylium‐SaltsOn a series of differently substituted flavyliumsalts1‐3their13C‐NMR‐chemical shifts and their1J(13CH) coupling constants were recorded and compared with results received by means of semiempirical PPP calculations and using LFE relationships. Both the experimental and theoretical results exhibit concordantly a characteristic alternate electron distribution along the conjugated π‐system of the compounds studies and reveal the distinct influence of donor and acceptor substituents on the electron distribution in both the benzopyrylium and the aryl moiety of the flavylium

ISSN:0021-8383    

DOI:10.1002/prac.19903320406

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

Abstract1‐Amino‐2(1 H)‐pyrimidinthiones1react with α‐haloketones2by S‐alkylation. Resulting 2‐carbonylmethylthiopyrimidinium salts3easily cyclise giving pyrimidothiadiazinium salts4. When treated with base the latter suffer a ring contraction affording mercaptopyrazolopyrimidines6in

ISSN:0021-8383    

DOI:10.1002/prac.19903320407

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

Non Steroidal Antiinflammatory Agents. V. Basic Esters of IndometacinThe reaction of diisopropylcarbodiimid1awith ethanolamines2a,baffords isoureas3a,bwhich in turn react with indometacin4to yield the title compounds6a,b. The noncatalyzed reaction of1a,bwith4(also in the presence of2) leads to the ureido‐indometacines8a,

ISSN:0021-8383    

DOI:10.1002/prac.19903320408

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractPhenacyl bromide1reacts with ethyl cyanoacetate2in presence of piperidine catalyst to afford the hexa‐2,4‐diene derivative5. Ethyl phenacylcyanoacetate3was obtained by reaction of1with the sodium salt6. Compound3reacts with hydrazines and trichloroacetonitrile to afford the pyrazoles7a,band the pyrroles8and9, respectively. The reflux of3in acetic/sulphuric acid mixture afforded the furan derivatives10an

ISSN:0021-8383    

DOI:10.1002/prac.19903320409

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe cycloaddition of C‐(2‐thenoyl)‐N‐arylnitrilimines2a,bto acrylic acid derivatives3‐5, fumaric acid derivatives9‐10, benzalmalononitrile14and N‐arylmaleimides20has been studied. Under thermal conditions these 1,3‐dipolar cycloadditions proceed with absolute regio‐chemistry to yield 5‐substituted‐2‐pyrazolines6‐8,11‐12,16and21, respectively. The cycloadducts11and16lose hydrogen cyanide to give the corresponding pyr

ISSN:0021-8383    

DOI:10.1002/prac.19903320410

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

Formation and Rearrangement of a Vinyl Peroxide Produced from the Reaction of 3‐Bromo‐2,3‐dimethyl‐2‐t‐butylperoxybutane with Silver HyponitriteThe reaction of 3‐bromo‐2,3‐dimethylbutane‐2‐hydroperoxide2with t‐butanol in the presence of sulfuric acid affords 3‐bromo‐2,3‐dimethyl‐2‐t‐butylperoxybutane3. The latter reacts with silver hyponitrite to yield t‐butoxypinacolone9. The mechanism of formation of9from3possibly proceeds via the carbocations6und7arising

ISSN:0021-8383    

DOI:10.1002/prac.19903320411

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

About the 1‐Camphenyl System – 1‐Camphenyl Compounds of Lithium, Tin and Mercury1‐Camphenyl lithium, 1‐camphenyl isobutyl mercury an 1‐camphenyl triethyl tin were synthesized and characterized by their13C n.m.r. spectra. The lithium compound contains σ,η1‐bonded allyl groups and suggests a weak interaction between the exocyclic double bonds and the metal atoms. The coupling constants1J(199Hg‐13C i‐C 4H 9) and1J(119Sn–13C C 2H 5) in the spectra of the mercury and the tin compound allow to compare the donor strength of 1‐camphenyl a

ISSN:0021-8383    

DOI:10.1002/prac.19903320412

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY