TY  - JOUR
SN  - 0385-5414
ID  - publicatio31957
UR  - https://doi.org/10.3987/com-93-s121
EP  - 1107
IS  - 2
A1  -  Fülöp Ferenc
A1  -  Sillanpää Reijo
A1  -  Dahlqvist Martti
A1  -  Pihlaja Kalevi
A1  -  Vainiotalo Pirjo
VL  - 37
SP  - 1093
JF  - HETEROCYCLES
N2  - In principle, the ring-chain tautomeric ratios of a number of 2-heteroaryl-substituted oxazolidines and tetrahydro-1,3-oxazines are well suited for determination of the Hammett-Brown sigma+ constants of heteroaryl substituents such as 2-furyl, 3-furyl, 3-thienyl and 2-pyrrolyl in CDCl3 solution and in the gas phase. However, a number of factors, and especially hydrogen-bonding, can change the monomeric character of either the ring or the chain form (or both), leading to deviations from the ideal sigma+ values. X-Ray analysis has demonstrated the chain structures of the products of the reactions of L-(-)-norpseudoephedrine and (+/-)-trans-2-aminomethylcyclohexanol with pyrrole-2-carboxaldehyde.
TI  - Ring-chain tautomerism and crystal structure of some 1,3-oxazacyclanes, and the electrophilic substituent constants for some heteroaryl groups in solution and in the gas-phase
Y1  - 1994///
AV  - restricted
ER  -