GB534916A - - Google Patents

Abstract

534,916. Vitamin B<SP>6</SP>. MERCK & CO., Inc. Dec. 13, 1939, No. 32111. Convention date, Dec. 27, 1938. [Class 2 (iii)] Vitamin B<SP>6</SP>, 3: 4-di(hydroxymethyl)- 5-hydroxy-6-methylpyridine, is prepared by a sequence of steps comprising (1) condensing ethoxyacetylacetone with cyanacetamide, (2) hydrolyzing the resulting 3-cyano-4-ethoxymethy]-6-methylpyridone-2 to form the lactone of 3 - carboxy - 4 - hydroxymethyl - 6 - methylpyridone-2, (3) treating the lactone with nitric acid to give the 5-nitro compound, (4) chlorinating the latter, e.g., with phosphorus pentachloride, (5) reducing the lactone of 2 - chloro - 3 - carboxy - 4 - hydroxymethyl - 5- nitro-6-methylpyridine so obtained, e.g., by means of hydrogen in the presence of palladium and platinum oxide as catalyst until 4 molecular equivalents of hydrogen have been absorbed, whereby the lactone of 3-carboxy-4-hydroxymethyl - 5 - amino - 6 - methylpyridine is produced, (6) diazotizing the latter to form the corresponding 5-hydroxy compound, and (7) reducing the said compound, e.g., with sodium amalgam or tin and hydrochloric acid, or with hydrogen under pressure in the presence of copper chromite. In a modification of the process, step (5) may be interrupted when only 3 molecular equivalents of hydrogen have been absorbed and the resulting lactone of 2-chloro- 3 - carboxy - 4 - hydroxymethyl - 5 - amino - 6 - methylpyridine isolated and subjected to further hydrogenation to eliminate the chloro group. An example is given. ' The Specification as open to inspection under Sect. 91 also refers to the use of alkoxyacetylacetones in step (1), and describes the interaction of methoxyacetylacetone, prepared by reacting methylmethoxyacetate and acetone in the presence of sodium, with cyanacetamide to produce 3 - cyano - 4 - methoxymethyl - 6 - methylpyridone-2. This subject-matter does not appear in the Specification as accepted.