Deutero pyridine

Castellucci, Sbrana and Verderame 223> report a phase transition at -60° in CSHSN (deutero pyridine), but could not induce a similar transition in normal pyridine (see also Loisel and Lorenzelli, 61>). May and Pace 224> report two phases in CH3SH and the deuterated CH3SD, using IR-techniques, as well as X-ray diffraction the transition takes place at 136 °K. Bruesch and Giinthard 225) report phase transitions for bicyclo (2.2.2) octane, triethylene-diamine and quinuclidine. 

Treatment of 3-phenylperhydro[l, 3]oxazolo[3,2-a]pyridine-5-carboxylates 303 and 304 with BF3 Et20 in THE, followed by reduction with NaBD4 afforded 6-deutero-4-phenylperhydropyrido[2,1 -c][l, 4]oxazin-1 -ones 220 and 222 (97JA6446). 

H-NMR Data for Organolithium-Pyridine Adducts and Some of Their 1-Deutero-1,2-Dihydropyridine Derivatives"... 

Oxidation of O-methyldeacetyllythramine (75) with chromic anhydride-pyridine complex yielded the ketone (79) which exchanged four hydrogens on treatment with sodium deuteroxide in deuterium oxide and deutero-methanol (12). 

Compound (8), under Vilsmeier formylation and nitration (nitric acid-acetic anhydride) conditions, proceeded as might have been expected for electrophilic substitution reactions to give the 1-substituted products (142) and (143). Reduction of (143) gave predominantly the imidazopyridine (144) with a small amount of the tetrahydro derivative (145) (81JCS(P1)78). Heating (8) in D2O led to the 1-deutero derivative (78HCA1755) via deuter-ation-deprotonation or via the tautomeric 2-(diazomethyI)pyridine tautomer of (8). 

Isomerization of l-deutero-l,3-dimethylindine at 30°C in pyridine,benzene, and methanol, using DABCO as catalyst, occurs with relative rates of 6.5, 1.14, and 1.0 respectively24 . The low relative rate in methanol is probably due to hydrogen bonding between the solvent and catalyst. The relative rates in the two aprotic solvents decrease in order of the decreasing dielectric constants of the solvents. 

This methodology is exemplified by two relatively recent syntheses of pyridoxol analogs. For the synthesis of [CD3]-pyridoxal 39b, the requisite deuterated oxazole 37, readily available from deutero-L-alanine, underwent Diels-Alder cycloaddition when heated to 135 C with a 20-fold excess of alkoxy dihydrofuran 38 to provide a 1 1 mixture of the regioisomeric pyridines 39a and 40 in 50-60% yield (Fig. 3.12)." Interestingly, the undesired regioisomer 40 can be quantitatively converted into 39a by treatment with ethanolic HCl. Treatment of 39a with dilute acid then provided hemiacetal 39b in 35-42% overall yield from the deutero-alanine. This route to 39a is clearly superior to the three-step conversion of pyridoxol to [CD3]-pyridoxal, which proceeds in 3% overall yield." ... 

The deutero-decarboxylation of isomeric pyridinecarboxylic acids is a good way of introducing deuterium into the pyridine nucleus. The 2- and... 

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