|
1. |
17O NMR spectroscopy: Intramolecular hydrogen bonding in hydroxypyridine carboxy esters |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 1-4
David W. Boykin,
Arvind Kumar,
Preview
|
PDF (229KB)
|
|
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
|
2. |
Analogues of the antibiotic puromycin as potential prodrugs of 3′‐amino‐3′‐deoxythymidine |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 5-9
Jesper Wengel,
Mohammed S. Motawia,
Erik B. Pedersen,
Carsten M. Nielsen,
Preview
|
PDF (343KB)
|
|
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
|
3. |
Synthesis of 5,6,8,9,14,14a‐hexahydroisoquino[1,2‐b][3]benzazepines |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 11-16
Dong H. Kim,
Preview
|
PDF (443KB)
|
|
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
|
4. |
Reactions of trichloroacetyl isothiocyanate with organic azides |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 17-23
Gerrit L'Abbé,
Joris Bosnian,
Suzanne Toppet,
Preview
|
PDF (404KB)
|
|
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
|
5. |
1,2‐fused pyrimidines. V. Synthesis of 1‐alkyl or phenyl‐2H‐dipyrido‐[1,2‐a:2′,3′‐d]pyrimidine‐2,5(1H)‐diones |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 25-31
Mario Di Braccio,
Giorgio Roma,
Gian Carlo Grossi,
Giovanni Ciarallo,
Preview
|
PDF (448KB)
|
|
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
|
6. |
1,4,4a,10b‐Tetrahydro‐N,N‐dimethyl‐4‐phenanthridinamines and 1,4,4a,5,6,10b‐hexahydro‐N,N‐dimethyl‐4‐phenanthridinamines |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 33-49
George Bobowski,
Barbara West,
Diana Omecinsky,
Preview
|
PDF (1133KB)
|
|
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
|
7. |
Synthesis of 1,3‐disubstituted‐5‐oxo‐7a‐methyl‐5,7a‐dihydroindoles |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 51-54
Mark R. Player,
Li‐Chang Wang,
Said M. Bayomi,
J. Walter Sowell,
Preview
|
PDF (253KB)
|
|
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
|
8. |
The synthesis and biological activity of new 7‐[2‐(cyanomethyl)piperazinyl]‐ and 7‐[3‐(cyanomethyl)piperazinyl]quinolone antibacterials |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 55-59
S. Gubert,
C. Braojos,
L. Anglada,
J. Bolós,
C. Palacin,
Preview
|
PDF (360KB)
|
|
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
|
9. |
Directed metalation of pyridinesulphonamides. Synthesis of pyridine‐fused isothiazoles and 1,2‐oxathioles |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 61-64
Babajide I. Alo,
Oluwole B. Familoni,
Francis Marsais,
Guy Queguiner,
Preview
|
PDF (248KB)
|
|
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
|
10. |
Synthesis of condensed quinoxalines. Part II |
|
Journal of Heterocyclic Chemistry,
Volume 29,
Issue 1,
1992,
Page 65-68
R. W. Sabnis,
D. W. Rangnekar,
Preview
|
PDF (318KB)
|
|
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
|
|