Pyridines 3- hydroxy-, methylation

Pyrrolo[3,2-c]pyridine, 4-hydroxy-tautomerism, 4, 500 Pyrrolo[3,2-c]pyridine, 2,3,3-trimethyl-methylation, 4, 513 Pyrrolo[3,4-6]pyridine, 2-methyl-UV spectra, 4, 501 Pyrrolo[3,4-c]pyridine, 2-methyl-UV spectra, 4, 501 Pyrrolopyridines acylation, 4, 504 bromination, 4, 505 diazo coupling, 4, 506 NMR, 4, 498... 

Treatment of alkyl 9-benzyloxycarbonyl-3-methyl-6-oxo-2/7,6//-pyr-ido[2,l-f ][l,3]thiazine-4-carboxylates with BBr3 in CH2CI2 at -70 °C for 0.5-1 h and at room temperature for 3h yielded 9-carboxyl derivatives. The decarboxylation of these acids was unsuccessful. Hydrolysis of diethyl cA-3,4-H-3,4-dihydro-3-methyl-6-oxo-2//,6//-pyrido[2,l-f ][l,3]thiazine-4,9-dicarboxylate in aqueous EtOH with KOH at room temperature for 3 days yielded 4-ethoxycarbonyl-3,4-dihydro-3-methyl-6-oxo-2//,6//-pyrido-[2,l-f ] [1,3]thiazine-9-carboxylic acid (00JCS(P1)4373). Alkyl 9-hydroxy-methyl-3-methyl-6-oxo-3,4-dihydro-2//,6//-pyrido[2,l-f ][l,3]thiazine-4-car-boxylates were O-acylated with AC2O and (PhC0)20 in pyridine at room temperature for 12-48h. 

Pyridine jV-Methyl- pyridinium 2-Pyridone 3-Hydroxy-pyridine 4-Pyridone Pyridine jV-oxide Unknown(s)... 

Isoxazolo[5,4-6]pyridine, 3,5-dimethy 1-,3C NMR, 6, 620 (79S449) Isoxazolo[5,4-6]pyridine, 3-methyl- H NMR, 6, 619 (77JHC435) Isoxazolo[5,4-6]pyridine, 3-methyl-5-phenyl-13C NMR, 6, 620 (79S449) Isoxazolo[2,3-a]pyridinium, 5-bromo-4-hydroxy- H NMR, 6, 619 <7UCS(C)1196>... 

Pyridin 3-Amino-4,5-bis-[hydroxy-methyl]-6-chlor-2-methyl-(Hydrochlorid) IV/ld, 158... 

Pyridin 3-Hydroxy-5-hydroxy-methyl-4-(hydroxy-sulfo-me-... 

The structure of the Co4 molecule is shown in Fig. 10. The four Co and four oxygens from four hydroxy methyl pyridine ligands form a cubane like central C04O4 structure. The molecule has S4 symmetry. Our NRLMOL calculations confirmed the ferromagnetic ordering indicated by experiment. However, the magnetic anisotropy barrier was found to be 23 K. In the... 

The lactone (31), obtainable in three steps from cholanic acid, served as the starting point in a different approach. Phosphorus oxychloride-pyridine dehydration of the corresponding hydroxy-methyl ester afforded a complex mixture of unsaturated esters in which the cis and trans non-conjugated esters (32) predominated Hydrolysis of the entire mixture and treatment of the mixture of free acids with iV-bromosuccinimide gave the new buf-20(22)-enolide (33). DDQ dehydrogenation of (33) could be controlled to yield either the desired bufa-... 

It was originally postulated that the methyl groups at C-4 were removed as COj -a suggestion that has proved to be correct. These groups are hydroxylated by a mixed-function oxidase which is NAD(P)H and Oj dependent. First, the 4a-methyl is attacked, yielding the 4 -hydroxymethyl-4 -methyl sterol. This reaction is catalyzed by a methyl sterol oxidase which has been solubilized and partially purified in Gaylor s laboratory [108]. The same enzyme preparation will, with reduced pyridine nucleotide and dioxygen, oxidize the C-30 carbon to a carboxylic acid. The 4a-methyl-4/8-hydroxymethyl-5a-cholestan-3j8-ol is not a substrate for sterol biosynthesis while its epimer is [5]. The detailed mechanisms for the enzymatic removal of C-30 and C-31 are not fully understood. The initial reaction yields a 4a-hydroxy-methyl sterol by inference however, neither the isolation nor the enzymatic formation of a 4a-hydroxymethyl sterol has been demonstrated in animal tissues. This may well result from the fact that the hydroxylation reaction is the slow step in the demethylation process [5]. 

Martinez and Joule (273) have described a very general route to the 6//-pyrido[4,3-ft]carbazole system involving y-aminoenone intermediates. Ketalization of 682 followed by indole N-methylation, pyridine N-methylation, and sodium borohydride reduction afforded 683. Mannich condensation gave a product which was hydrolyzed to the y-aminoenone 684. When 684 was refluxed in 50% aqueous acetic acid the hydroxy tetrahydro 6//-pyrido[4,3-Z> Jcarbazole 685 was produced in 25% yield. 

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