Methoxy amine

The Addition of Methoxy/amine to 3 -Hydroxypregna-5, 16-dien-20-one Acetate ... 

The direct oxidation of unsaturated N-methoxy amines also leads to the formation of cyclic products (Scheme 11) [30]. 

Low-density lipids in the blood cause cholesterol deposits. Their presence and nature, including the position and number of double bonds, can be analyzed by means of ESI-MS techniques <2000JMP224>. Reverse-phase HPLC microsamples containing phospholipids were treated with bis(trimethylsilyl) trifluoroacetamide, then with methoxy-amine, and then exposed for 8 min to ozone gas at room temperature ESI-MS followed and showed the fragments corresponding to ozonides. 

Preparative Methods these chiral methoxy amines are readily prepared from (5)- or (/f)-phenylalanine via reduction followed by methylation. ... 

The benzoyloxymethyl group of the pyrido[2,l-6]quinazolinones 211 (R = PhCOOCHj) was hydrolyzed to a hydroxymethyl group in a mixture of concentrated hydrochloric acid and ethanol under reflux conditions. The acetyl group of the pyrido[2,1 -6]quinazolinone 211 R = COMe was converted to a 1-(methoxyimino)ethyl group by reaction with methoxy-amine hydrochloride in pyridine at room temperature for 3 days. ... 

The monomeric structural unit of the 3-alkylpiperidine alkaloids is readily apparent in a number of simple 3-alkylpyridines isolated from marine sponges. In all known examples, the 3-alkyl component of the monomeric unit is attached to a primary amine, methyl amine, methoxy amine, methoxy methyl amine, imine oxide or oxime methyl ether functionality at the distal terminus. 

Niphatynes A (1) and B (2) isolated from a Niphates sp. collected off Vitu Levu in the Fijian Islands were the first reported examples of monomeric 3-alkylpyridines from sponges [17]. These two metabolites, which contain the alkyne and methoxy amine functionalities encountered in many of the monomeric 3-alkylpyridines, were reported to be cytotoxic to murine leukemia P388 in vitro (niphatyne A (1) ED50 0.5 [ig/ml). Niphatesines A (3), B (4), C... 

The structural unit of this subtype of polycyclic alkaloid is a 3-alkyl substituted pyridine, where remote terminal oxime, amine, methoxy amine, nitro, imine oxide or methoxy-oxime fuctionalities are characteristic in the monomeric forms. Polymeric pyridinium salts attached to a long linear carbonated chain through positions 1 and 3 are a substructural feature in a second subgroup of alkaloids. Related reduced dihydropyridinium salts have also been known since the discovery of haliclamine A and B. (See Tables 5 and 6 for C-NMR data). 

The second one involves highly stereoselective reduction of the 7-imino compound (88) with sodium cyanoborohydride under acidic condition at pH 3 in methanol, giving the 7P-isomer as the sole product in 90% yield [36]. The unique stereochemical outcome can be rationalized as follows. In an acid medium, sodium cyanoborohydride may produce a molecular complex of hydrogen cyanide and borane, HCN BH3, and this species reacts with either 7-methoxy amine (77) or 7-imine (88) to form (89) or (90), respectively. The methoxy-amine complex (89) may be converted into the imine-borane complex (90), which undergoes reduction with intramolecular hydride reduction either directly via (91) or more probably via a six-membered transition state (92). 

Jen and co-workers at Smith, Kline and French (1973) also utilized imine sulfenylation (NaH-DMF-CH2SS02CH3) to secure 334 and were subsequently able to perform transformations similar to 337-339 (thien-ylacetyl side chain) with silver nitrate in methanol. On the other hand, these workers also found that 7a-methylthioamine 358 reacted with mercuric chloride in methanol-DMF-pyridine to yield stereospecifically the crystalline 7a-methoxyamine 359 in 80% yield. This proves to be a desirable route to many semisynthetic cephamycins, since it is short, is stereocontrolled, and proceeds through the very versatile 7a-methoxy-amine intermediate. 

In a synthesis of C-3 acetoxycephamycin analog 476, Ratcliffe and Christensen (1972) used excess BOC-a-trichloroethyl-o-a-aminodipoyl chloride (474) to acylate 7-amino-7a-methoxycephalosporin benzhydryl ester (475) (pyridine-methylene chloride, 0°C). A 48% yield of the desired acylated product (476) was obtained, contaminated with about 14% isomer. Lunn and Mason (1974) employed similar conditions to acylate 475, whereas Sankyo researchers (Nakao et al., 1976) acylated 477 with unstable (cyanomethylthio)acetyl chloride and N,N -dimethylaniline (1,2-dichloroethane) to obtain CS1170 (478). The use of dicyclohexyl car-bodiimide has also been employed by DeMartinis and co-workers (1976) in condensing trifluoromethylthioacetic acid to a variety of 7a-methoxy-amine esters. 

Wataya Y, Sonobe Y, Maeda M, Yamaizumi Z, Aida M, Santi DV (1987) Reaction of 5-trifluoromethyl-2 -deoxyuridine and l-methyl-5-trifluoromethyluracil with methoxy-amine model studies for the interaction between thymidylate synthetase and 5-trif luoromethyl-2 -deoxyutidine 5 -phosphate. J Chem Soc Perkin Trans 1 2141-2147... 

---