摘要:

AbstractNatural abundance17O nmr chemical shift data for 8 aryl esters and 10 pyridine carboxy esters, including 6ortho‐hydroxy esters, recorded in acetomitrile at 75° are reported. The carbonyl group17O nmr chemical shift data for methyl 2‐, 3‐ and 4‐pyridinecarboxylate are correlated with σ+constants. The hydrogen bonding component (ΔδHB) to the ester carbonyl17O nmr chemical shift for the intramolecular hydrogen bondedortho‐hydroxy systems are 9.8 ppm, 13.6 ppm and 4.3 ppm for benzoates, 2‐pyridinecarboxylates and 4‐pyridinecarboxylates, respectively. The relationships of the ester ΔδHBvalues to other hydrogen bond acceptor ΔδH

ISSN:0022-152X    

DOI:10.1002/jhet.5570290101

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractCondensation of L‐ and D‐3′‐amino‐2′,3′‐dideoxynucleosides2–5withN‐BOC‐protected aminoacids6and13using dicyclohexylcarbodiimide andN‐hydroxysuccinimide in DMF is reported to give theN‐BOC‐protected acylamino aminonucleosides 7–9and14in 51–81% yield. After deprotection using trifluoroacetic acid the corresponding unprotected new analogues of puromucin10–12and15were obtained in 43–56% yield. These compounds did not show any significant antiviral activity using HIV (stain HTLV‐III B)

ISSN:0022-152X    

DOI:10.1002/jhet.5570290102

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractSyntheses of 5,6,8,9,14,14a‐hexahydroisoquino[1,2‐b][3]benzazepine‐2,3,11,12‐tetrol and related compounds are described. Key steps involve an initial construction of the isoquinoline ring under the Bischler‐Napieralski conditions, which is followed by the building of the azepine ringviaan intramolecular lactam formation on to the isoquinolin

ISSN:0022-152X    

DOI:10.1002/jhet.5570290103

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractBenzyl azide reacts with trichloroacetyl isothiocyanate to give7ain chloroform solution, and11in acetone solution. These 1,2,4‐oxathiazolidines were characterized by13C nmr spectroscopy (Scheme 2), but could not be isolated since they deterioratedviathe carbodiimide8ainto the 1,2,4‐thiadiazolidine9a. The oxathiazoline6ais assumed as an intermediate and was trapped by isocyanates and dicyclohexylcarbodiimide to give the 1,2,4‐thiadiazolidines10a,band12respectively. Isopropyl azide also reacts with trichloroacetyl isothiocyanate to give the labile oxathiazolidine7b, which decomposes to the carbodiimide8band the 1,2,4‐thiadiazolidine9b. In the case of diphenylmethyl azide, however, no evidence was obtained for the presence of the oxathiazolidine7cin the1H nmr spectra; only the carbodiimide8cwas observed. A mechanistic rationalization is presented in S

ISSN:0022-152X    

DOI:10.1002/jhet.5570290104

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractThe reaction of 2‐[(N‐acyl,N‐alkyl or phenyl)amino]‐4H‐pyrido[1,2‐a]pyrimidin‐4‐ones8a‐gwith theN,N‐dimethylformamide/phosphorus oxychloride Vilsmeier reagent1(95°, 90 minutes) afforded 1‐alkyl or phenyl‐2H‐dipyrido[1,2‐a:2′,3′‐d]pyrimidine‐2,5(1H)−diones, 3‐alkyl substituted or not,10a‐g.The starting compounds8were prepared by treating 2‐amino‐4H‐pyrido[1,2‐a]pyrimidin‐4‐onesN‐alkyl substituted7a,borN‐phenyl substituted4with excess anhydrides (130°, 7 hours) when the 2‐(alkylamino) derivatives7were used in the reaction, compounds8were obtained along with very small amoun

ISSN:0022-152X    

DOI:10.1002/jhet.5570290105

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractSynthetic procedures to prepare the title compounds are described. Diels‐Alder cycloaddition of β‐nitrostyrene derivatives5toN,N‐dimethyl‐1,3‐butadien‐1‐amine,6, gave 5‐aryl‐N,N‐dimethyl‐6‐nitro‐2‐cyclohexen‐1‐amines 7. Reduction of 7 with zinc in acetic acid gave the diamino derivatives8. Schotten‐Baumann acylation of8gave amides9. Treatment of8with alkyl isocyanates gave the aminourea derivatives10. Bischler‐Napieralski cyclodehydration procudure of9and10gave 1,4,4a,10b‐tetrahydrophenanthridinamines3andN6‐alkyl‐1,4,4a,10b‐tetrahydro‐N4,N4‐dimethyl‐4,6‐phenanthridinediamines11, respectively. Condensation of diamines8with aryl aldehydes under azeotropic conditions gave imines12which on treatment with acids yielded 6‐aryl‐1,4,4a,5,6,10b‐hexahydro‐N,N‐dimethyl‐4‐phenanthridinamines4. The stereochemistry of thes

ISSN:0022-152X    

DOI:10.1002/jhet.5570290106

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractCycloaddition and addition reactions of ethyl propiolate with a series of 1,3,5‐substituted‐2‐amino‐4‐methylpyrroles to form, 1,3‐disubstituted‐5‐oxo‐7a‐methyl‐5,7a‐dihydroindoles are described. High resolution mass spectral and

ISSN:0022-152X    

DOI:10.1002/jhet.5570290107

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractSome novel 7‐[2‐ or 3‐(cyanomethyl)piperazinyl]quinolones have been prepared. Most notable, 2‐cyanomethyl‐piperazine5and 1‐methyl‐2‐cyanomethylpiperazine8at the quinolone C‐7 position produce products with goodin vitroantibacterial activity. The key step in the synthesis of these products involves the regioselective deprotection of the benzyl group in function of

ISSN:0022-152X    

DOI:10.1002/jhet.5570290108

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

Abstract4‐Lithio‐N‐t‐butylpyridine‐3‐sulphonamide reacted with benzophenone and carbon dioxide respectively to give the corresponding intermediates which on appropriate treatment gave isothiazolo[5,4‐c]pyridin‐3‐one 1,1‐dioxides. Metalation of 2‐ and 4‐(N,N‐dialkylaminosulphonyl)pyridines with lithium diisopropylamide (LDA) gave anions which reacted with benzophenone to give carbinols which thermally cyclised to 1,2‐oxathiolo[3,4‐b]pyridine and 1,2‐oxathi

ISSN:0022-152X    

DOI:10.1002/jhet.5570290109

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY

摘要:

AbstractA novel efficient synthesis of fluorescent, fused quinoxalines was achieved. 7‐Triazolyl‐1,4‐dioxino[2,3‐b]‐quinoxalines were synthesized by the diazotisation of 7‐amino‐1,4‐dioxino[2,3‐b]quinoxaline and coupling with selected aromatic amines followed by air oxidation. Diazotised aryl amines were coupled with 7‐amino‐1,4‐dioxino[2,3‐b]quinoxalines followed by subsequent air oxidation afforded 1,4‐dioxino[2,3‐b]quinoxalino‐[6,5‐d]1,2,3‐triazoles. 7‐Amino‐1,4‐dioxino[2,3‐b]quinoxaline was condensed with conjugated enol ethers followed by cyclization in dowtherm resulted in 1,

ISSN:0022-152X    

DOI:10.1002/jhet.5570290110

出版商:Wiley‐Blackwell    

年代:1992

数据来源: WILEY