𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Structural studies on 6-methyl-9-carbamoyl-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-ones by 1H, 13C and 15N NMR spectroscopy

✍ Scribed by Gábor Tóth; Carlos de La Cruz; István Bitter; István Hermecz; Béla Pete; Zoltán Mészáros

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
555 KB
Volume
20
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Several 6-methyl-9-carbamoyltetrahydro-4H-pyrido[l,2-a]pyrimid~-4-ones have been prepared using phosgene iminium chloride. These compounds can exist in equilibrium as the cis (3A) imine$(3B) enaminee trans (3C) imine. 'H, 13C and "N NMR prove that the cis-and trans-imine isomers are predominant in the equilibrium. ' H NMR data reveal that the share of the 3B enamine form is negligible at measurable concentrations. The isomeric ratio 3A:3C is time dependent and can be monitored by measuring the CH3-C-6 and (CH,),N signals. The 13C NMR data show that doublets in the range 42-45 ppm for C-9 are only compatible with the d i n e forms 3A and 3C. The SCS values of the CH3-C-6 and OCN(CH,), groups were calculated and used for identification of the cis and trans isomers. 15N NMR data show that the N-1 chemical shift of the imine is approximately -140 ppm for compound 3, whereas that of a fixed enamine is around -267.8. This provides additional support for the predominance of the imine tautomers in the equilibrium 3A 3B $3C. "N data also allow the stereoisomers 3A and 3C to be distinguished.

📜 SIMILAR VOLUMES

Catalytic hydrogenation of 3-benzyloxyca
Catalytic hydrogenation of 3-benzyloxycarbonylaminoazino[1,2-x]-azin-4-ones. A facile access to 3-amino-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyridin-4-ones and 3-Amino-6,7,8,9-tetrahydro-4H-azino[1,2-x]pyrimidin-4-ones
✍ Simon Rečnik; Renata Toplak; Jurij Svete; Lucija Pizzioli; Branko Stanovnik 📂 Article 📅 2000 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 615 KB

## Abstract By catalytic hydrogenation of 3‐(benzyloxycarbonyl)amino‐4__H__‐pyrido[1,2‐__a__]pyridin‐4‐ones **28** and **29**, and azino[1,2‐__x__]pyrimidin‐4‐ones **32–35, 41**, and **42**, partial saturation of the heterocyclic systems and removal of the benzyloxycarbonyl moiety was observed to g

ChemInform Abstract: Catalytic Hydrogena
ChemInform Abstract: Catalytic Hydrogenation of 3-Benzyloxycarbonylaminoazino[1,2-x]azin-4-ones. A Facile Access to 3-Amino-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyridin-4-ones and 3-Amino-6,7,8,9-tetrahydro-4H-azino[1,2-x]pyrimidin-4-ones.
✍ Simon Recnik; Renata Toplak; Jurij Svete; Lucija Pizzioli; Branko Stanovnik 📂 Article 📅 2001 🏛 John Wiley and Sons ⚖ 29 KB 👁 1 views

## Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable v

1H{15N} GHMQC study of 5,7-diphenyl-1,2,
1H{15N} GHMQC study of 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine and 1H, 13C and 15N NMR coordination shifts in Au(III) chloride complexes of 1,2,4-triazolo[1,5-a]pyrimidines
✍ Edward Szłyk; Leszek Pazderski; Iwona Łakomska; Lech Kozerski; Jerzy Sitkowski 📂 Article 📅 2002 🏛 John Wiley and Sons 🌐 English ⚖ 105 KB

## Abstract The ^1^H{^15^N} NMR spectrum of 5,7‐diphenyl‐1,2,4‐triazolo[1,5‐__a__]‐pyrimidine (**3**) was measured by GHMQC, unambiguously assigned and compared with the spectra of 1,2,4‐triazolo[1,5‐__a__]pyrimidine (**1**) and 5,7‐dimethyl‐1,2,4‐triazolo[1,5‐__a__]pyrimidine (**2**). A series of

13C and 15N NMR chemical shift assignmen
13C and 15N NMR chemical shift assignments of N-1-(2- azidoethyl)-4-R-pyrimidin-2-ones by 1H,X HMQ(B)C with z-gradient selection
✍ Erkki Kolehmainen; Kari Lappalainen; David Šaman; Antonin Holý; Jaroslav Günter 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 181 KB 👁 1 views

13C and 15N NMR chemical shift assignments based on z-gradient selected 1H,X (X \ 13C and 15N) HMQC and HMBC experiments are reported for N-1-(2-azidoethyl)pyrimidin-2-one (ring system of cytosine), its Ðve 4-R derivatives [where and and 2-azidoethyl tosy ) 2 ] late. The possibilities of detecting