2- C- methyl derivative

Brimacombe s group has described an attempt to prepare relatives of leucodrin (305) and conocarpin (306) by intramolecular Michael cyclization of the enolate anion obtained by demethylation of 2-0-(jE)-cinnamoyl-5,6-0-isopropylidene-3-0-methyl-L-ascorbic acid (307). However, treatment of (307) with lithium iodide in DMSO furnished the isomeric 2-C-methyl derivative (308) by remethyla-tion of the enolate anion by the liberated methyl iodide. 

Pyrazole and its C-methyl derivatives acting as 2-monohaptopyrazoles in a neutral or slightly acidic medium give M(HPz) X, complexes where M is a transition metal, X is the counterion and m is the valence of the transition metal, usually 2. The number of pyrazole molecules, n, for a given metal depends on the nature of X and on the steric effects of the pyrazole substituents, especially those at position 3. Complexes of 3(5)-methylpyrazole with salts of a number of divalent metals involve the less hindered tautomer, the 5-methylpyrazole (209). With pyrazole and 4- or 5-monosubstituted pyrazoles M(HPz)6X2... 

The ratio, at equilibrium, of the hydrated to anhydrous forms (for both neutral species and anions) has been measured for the following 2-hydroxjrpteridine and its 4-, 6-, and 7-methyl and 6,7-dimethyl derivatives 6-hydroxypteridine and its 2-, 4-, and 7-methyl derivatives 2,6-dihydroxypteridine and 2-amino-4,6-dihydroxypteridine. The following showed no evidence of hydration 4- and 7-hydroxy-pteridine 2,4-, 2,7-, 4,7-, and 6,7-dihydroxypteridine and 2-amino-4-hydroxypteridine. The kinetics of the reversible hydration of 2-hydroxypteridine and its C-methyl derivatives (also 2-mercapto-pteridine) have been measured in the pH region 4-12, and all these reactions were found to be acid-base cataljrzed. The amount of the hydrated form in the anions is always smaller than in the neutral species, but it is not always negligible. Thus, the percentages in 2-hydroxy-, 2-hydroxy-6-methyl-, 2-mercapto-, and 2,6-dihydroxypteridine are 12, 9, 19, and 36%, respectively (see also Table VI in ref. 10). 

KUZUYAMA, T., TAKAGI, M., KANEDA, K, WATANABE, H, DAIRI, T., SETO, H., Studies on the nonmevalonate pathway conversion of 4-(cytidine 5 -diphospho)-2-C-methyl-D-erythritol to its 2-phospho derivative by 4-(cytidine 5 -diphospho)-2-C-methyl-D-erythritol kinase, Tetrahedron Lett., 2000, 41, 2925-2928. 

Fig. 2 Two possible biosynthetic pathways to pyrethrolone. The [l-13C]D-glucose-derived 13C labels that occur in the mevalonic acid and 2-C-methyl-D-erythritol 4-phosphate (13) pathways are colored in red and green, respectively. The phosphate moiety is indicated as P ...

The presence of a dichloromethylene group at the anomeric center of 82 facilitates proton abstraction at C-3 by a strong base (77), aifording the 4-deoxyglycos-3-ulose derivative 83. Reduction of the dichloromethylene group by Raney nickel gave a 1-C-methyl derivative with high stereospecificity, which opens the way to a series of 2,5-anhydro-l-deoxyalditols. Compound 83 was the key intermediate for the synthesis (78) of tosyl L-(+)-epi-muscarine (84a) and tosyl L-(+)muscarine (84b). 

Methyl phenyl- or p-chlorophenylglycinate afforded with 4-chloroquino-line-3-carboxylate a pyrrolo[3,2-c]quinoline derivative 130 [89H(29)899]. Alkyl a-(2-quinolyl)glycinate was transformed into imidazo[l,5-a]quinoline 131 with DMF-DMA, TOF, or DEMA f91JHC1715, 91ZN(B)1110]. 

A simple synthesis of the branched chain sugar, 2-C-methyl-D,L-lyxofuranoside 17 has been achieved by using the tin(ll) enolate of a I 3-dihydroxy-2-propanone derivative and methyl pyruvate (23). 

There is only one report of an alkylation of compound 1 to give a methiodide of unspecified structure.10 There are no reports of alkylation of compound 2 or of its derivatives but many reports of alkylation of derivatives of compound 3, particularly in the preparation of Trazadone (6) and related compounds. Methylation of the parent 3 and its C-methyl derivatives has been thoroughly examined by Paudler and Brumbaugh.218... 

C-Methyl-L-erythrose (6) and derivatives 2-C-Methyl-D-erythrono-l,4-lactone (7)... 

H. Yamamoto, H. Sasaki, and S. Inokawa, Reaction of lithium dimethyl cuprate with methyl 2,3-anhydro-5-deoxy-a-D-ribofuranoside. A new, convenient route for the preparation of 2,5-dideoxy-2-C-methyl-D-arabinofuranose derivatives, Carbohydr. Res. 100 C44 (1982). 

D. R. Hicks and B. Fraser-Reid, The 2- and 3-C-methyl derivatives of methyl 2,3-dideoxy-a-D-e/yfhro-hex-2-enopyranoside-4-ulose, Can. J. Chem. 53 2017 (1975). 

L-Olivose (2,6-dideoxy-L-arabino-hexose, 55L) is not common in Nature. The 3-C-methyl derivative, L-oleandrose has been found in oleandomycin, a macro-lide antibiotic produced by Streptomyces antibioticus. Interestingly, it was proved that methylation occurs in the L-oliviosyl glycoside once L-olivose is transferred to the aglycone.150... 

Treatment of the oxathiazolidine (55) at 140 °C with PhNH2 or PhC02H leads to SN attack at the oxy carbon, with loss of S02 and formation of 2-substituted aminoethanes (68BCJ1925). Likewise, C-methyl derivatives, e.g. (164), are catalytically isomerized at sulfur by halide ions to an equilibrium mixture of cis and trans isomers via the intermediates (165) (75BCJ929). 

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