TY - JOUR
T1 - Formation and Reactions of Heteroaromatic Anions in the Gas Phase
AU - DePuy, Charles H.
AU - Bean, Gerritt P.
AU - Kass, Steven R.
PY - 1988/9/1
Y1 - 1988/9/1
N2 - The gas-phase acidities of furan, thiophene,pyridine, 1-methylpyrrole, and a number of their methyl derivatives have been determined in a flowing afterglow apparatus. The △Gacid (kcal/mol) and site of deprotonation of the parent heterocycles are as follows: furan 380 ± 3 (2-position), thiophene 373 ± 3 (2-position), pyridine 384 ± 3 (3- and/or 4-position), 1-methylpyrrole 386 ± 3 (methyl group). For the methylated species studied the acidities are 2-methylfuran 377 ± 3, 2-methylthiophene 373 ± 3, 3-methylthiophene 373 ± 3, 3-methylpyridine 371 ± 3, 2-methylpyridine 370 ± 3, and 4-methylpyridine 368 ± 3. The relative acidities of the hydrogens in the other sites in these molecules have been estimated by hydrogen-deuterium exchange studies and by other chemical methods. Anions (M - 1) from these molecules have been allowed to react with N2O, O2, COS, and CS2 and the ionic products determined. The gas-phase acidities have been compared with those calculated by the semiempirical methods AMI and MNDO.
AB - The gas-phase acidities of furan, thiophene,pyridine, 1-methylpyrrole, and a number of their methyl derivatives have been determined in a flowing afterglow apparatus. The △Gacid (kcal/mol) and site of deprotonation of the parent heterocycles are as follows: furan 380 ± 3 (2-position), thiophene 373 ± 3 (2-position), pyridine 384 ± 3 (3- and/or 4-position), 1-methylpyrrole 386 ± 3 (methyl group). For the methylated species studied the acidities are 2-methylfuran 377 ± 3, 2-methylthiophene 373 ± 3, 3-methylthiophene 373 ± 3, 3-methylpyridine 371 ± 3, 2-methylpyridine 370 ± 3, and 4-methylpyridine 368 ± 3. The relative acidities of the hydrogens in the other sites in these molecules have been estimated by hydrogen-deuterium exchange studies and by other chemical methods. Anions (M - 1) from these molecules have been allowed to react with N2O, O2, COS, and CS2 and the ionic products determined. The gas-phase acidities have been compared with those calculated by the semiempirical methods AMI and MNDO.
UR - http://www.scopus.com/inward/record.url?scp=0000696801&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000696801&partnerID=8YFLogxK
U2 - 10.1021/jo00254a001
DO - 10.1021/jo00254a001
M3 - Article
AN - SCOPUS:0000696801
SN - 0022-3263
VL - 53
SP - 4427
EP - 4433
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 19
ER -