2-Hydroxy-6-methyl-pyridines

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... 

A second enzymatic site, which has been selected as a target to direct the chelating potential of the thiosemicarbazone molecule, is pyridoxal phospho-kinase [65], This catalyst is a zinc-requiring enzyme [66] that catalyzes the phosphorylation of pyridoxine at position 5 to form the active coenzyme form. In an effort to accomplish inhibition, 2-formyl-3-hydroxy4,5-bis(hydroxy-methyl)pyridine thiosemicarbazone (117) was synthesized [65]. This was accomplished by two different procedures. The common intermediate, 3-acetoxy-2,4,5-tris(acetoxymethyl)pyridine (111) [67], upon acid hydrolysis afforded 3-hydroxy-2,4,5-tris(hydroxymethyl)pyridine hydrochloride (112), which was treated with hydrogen chloride as a suspension in acetone [68]. The amount of hydrogen chloride taken up by the suspension is a critical factor and. 

Methyl-3-hydroxy-4,5-bis-(hydroxy methyl)-pyridine 2-Ethyl -3-hydroxy-4,5-bis- (hydroxy- 1 1 1 1... 

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. 

Auch bei der Reduktion von 3-Hydroxy-2-methyl-pyridin-4,5-dicarbonsaure-dime-thylester mit Natriumboranat/Aluminiumchlorid bei 20° in Gegenwart eines Alumini-umchlorid-Uberschusses wird in 57%iger Ausbeute 3-Hydroxy-2-methyl-4-hydroxyme-thyl-pyridin-5-carbonsaure-4 -lacton erhalten3. 

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 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]. 

Auf die gleiehe Wcise wird 2-(2-IIydroxy-athyl)-, 2-(3-Hydroxy-propyl)- und 2-Propyl-pyridin abgebaut. Durch Bestrahlung in Tetrahydrofuran wird 2-Methyl-pyridin gebildet1. In 3- oder 4-Stcllung entsprechend substituierte Pyridine bleiben unter diesen Reaktionsbedingungen unverandert. 

Ober Rhodium/Aluminiumoxid werden 3-Hydroxy-2-(dimethylamino-methyl)-pyri-din sowie 3-Hydroxy-2,6-bis-[dialkylamino-methyl]-pyridine in Salzsaure bei 307140 bzw. 160 bar mit sehr guten Ausbeuten zu den entsprechenden Piperidinen hydriert1 2. 3-Hydroxy-6-propyl-pyridin liefert mit Platin(IV)-oxid in Essigsaure (2073 bar) 96% d.Th. 3-Hydroxy-6-propyl-piperidin3. Analog werden 3-Hydroxy-l-alkyl-pyridinium-bromide iiber Raney-Nickel in Wasser (1507130 bar) hydriert4. 

Methyl-3-benzoyl-piperidin (—40% d.Th.) erhalten wird1, vgl- 2. Aus 3-Acetyl-pyridin entstehen, abhangig von Katalysator und Losungsmittel, 3-(l-Hydroxy-athyl)-pyridin oder 3-Acetyl-1,4,5,6-tetrahydro-pyridin1 bzw. Gemische aus beiden 1 vgli a- 4. 

Parinol 3-[hydroxy-bis(4-chlorophenyl)methyl]pyridine (12), is similarly effective against the powdery mildew fungi of ornamental plants. It is a protective... 

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