Phenacyl 2 methyl

In 1937, Kondo and Nagasawa confirmed the reactivity of the sole 2-methyl group in the condensation of 2,4-dimethylthiazole with benzal-dehyde (505) and in the cyclizafion to tbiazolopyrrole in the reaction with phenacyl bromide (506) (Scheme 113). 

Isotubaic acid — see Benzofuran-5-carboxylic acid, 4-hydroxy-2-isopropyl-Isouramil occurrence, 3, 144 5-Isoxalones potentiometry, 6, 11 Isoxanthopterin, 6-acetonyl-structure, 3, 276 Isoxanthopterin, 3,8-dimethyl-rearrangements, 3, 309 Isoxanthopterin, 6-methoxy-3,8-dimethyl-synthesis, 3, 297 Isoxanthopterin, 6-methyl-bromination, 3, 301 Isoxanthopterin, 8-methyl-synthesis, 3, 319 Isoxanthopterin, 6-phenacyl-structure, 3, 276... 

Thiazolylium salts, 2-methyl-3-phenacyl-reactions, 6, 293 Thiazolylium tosylate, 3-methyl-UV spectroscopy, 6, 240 Thiazolyl radicals... 

Xanthopterin, 7,7-dimethyl-7,8-dihydro-synthesis, 3, 315 Xanthopterin, 7-methyl-synthesis, 3, 303 Xanthopterin, 7-phenacyl-structure, 3, 276 Xanthopterin, 3,5,7-trimethyl-Claisen condensation, 3, 303 Xanthopterin-7-carboxylic acid reactions... 

Lobinine, CjgHggOgN. First isolated by Wieland, Ishimasa and Koschara who, on the evidence then available, regarded it as 2-phenacyl-l-methyl-7-)3-hydroxypropylhexamethyleneimine, CjgHjjOjN (XXI), which was modified to (XX) in 1989. It furnishes an oxime (B. HCl, m.p. 182°) and a benzoyl derivative (B. HCl, m.p. 146-7°). On reduction by sodium in acetic acid it is converted into the unsaturated dihydric alcohol for which th original name lobinol has been changed to /3-lobinanidine,... 

A variety of 2-substituted indoles can be prepared by the Gassman process. For example, when methyl phenacyl sulfide 22 was employed with aniline, the 2-phenyl indole was obtained in 81% yield as shown here. 

Thiopyrones and selenopyrones can be alkylated more readily than pyrones. Thus 2,6-dimethyl-4/f-pyran-4-thionc (4,6-dimethyl-4-thiopyrone) (23, Y = S) reacts rapidly with methyl iodide yielding a 4-methylmercaptopyrylium iodide (24, Y = S, R = Me, X = I). Many alkylating agents were investigated by King et al. The kinetics of the reaction between 2,6-dimethyl-4-thiopyrone and substituted phenacyl bromides was found to be described by the Hammett... 

It should be noted that a considerable acceleration of the reaction for low-reactive 4-iodopyrazoles is observed for substrates in which acceptor substituents at the pyrazole nitrogen atom additionally play the role of protecting group. Thus, it has been shown (88M253) that iV-phenacyl- and iV-p-tosyl-4-iodopyrazoles interact with phenylacetylene, 2-methyl-3-butyn-2-ol, and trimethylsilylacetylene at room temperature for 3-24 h in 70-95% yields (Scheme 56). 

These workers used binary solvent systems over a range of mole fractions to determine, for each solute, the constants a and b of equation (8.2). For methyl and phenacyl esters, TLC was used, while overpressured layer chromatography (OPLC) was used for dansyl amino acids. Nurok and co-workers (11) also evaluated how the quality of a simulated separation varies with changing solvent strength by using the inverse distance function (IDF) or planar response function (PRF), as follows ... 

Another cyclisation involving 4-amino-6-methyl-3-thioxo-l,2,4-tiiazin-5-one 82 is the reaction with propargyl bromide followed by palladium(II) catalysis to yield a [1,2,4] triazino[3,4-f ][l,3,4]thiadiazine 83, or with phenacyl bromide to give 84 <96MI03 96CA(125)195597 96MI04 96CA(125)247767 >. 

The methyl hydrogens in 1,3,5- and 1,4,5-trimethyl tetrazoliums, as well as the proton on C-5 in 2,3-disubstituted tetrazoliums are acidic, and can be abstracted with butyl lithium.289,290 Tetrazolium methylides, e.g., the dicyano derivative (143), and the phenacyl compound (171, R = Ph, R = Me) are known.291 The latter undergoes an unexpected thermal cyclization reaction to yield imidazolones (173) (Scheme 27).292... 

In the reaction of 2-acetylpyridines and phenacyl bromide, l-hydroxy-l-methyl-3-phenyl-l//-pyrido[2,l-c]-[l,4]oxazinium bromide was obtained <2005JST(743)7>. 

Amino-8-cyano-3-methyl-4-oxo-6/7-[l,2,4]triazino[3,4-7][l,3,4]thiadiazine 16 when reacted with phenacyl bromide in the presence of triethylamine in acetonitrile afforded a novel heterocyclic system 27 (Equation 1) <2004IJH181>. 

The indolo analogue 25 was prepared (86AP659) by alkylation of 9-methyl-3,4-dihydro-/3-carboline 23 with phenacyl bromide followed by perchloric acid to give 24. Reaction of 24 with hydrazine hydrate gave triazinopyridoindole 25, which underwent 1,126-dehydrogenation with Hg(II)-EDTA (86AP659). 

Treatment of 3-methyl-6-(l-methylhydrazino)uracil 262 with phenacyl bromides in ethanol afforded (78H1571 81CPB379) the pyrimido-[4,3-c][l,2,4]triazines 264 in addition to 263. 

Asymmetric induction using catalytic amounts of quininium or A-methyl-ephedrinium salts for the Darzen s reaction of aldehydes and ketones with phenacyl halides and chloromethylsulphones produces oxiranes of low optical purity [3, 24, 25]. The chiral catalyst appears to have little more effect than non-chiral catalysts (Section 12.1). Similarly, the catalysed reaction of sodium cyanide with a-bromo-ketones produces epoxynitriles of only low optical purity [3]. The claimed 67% ee for the phenyloxirane derived from the reaction of benzaldehyde with trimethylsul-phonium iodide under basic conditions [26] in the presence of A,A-dimethyle-phedrinium chloride was later retracted [27] the product was contaminated with the 2-methyl-3-phenyloxirane from the degradation of the catalyst. 

Stabilized telluronium ylides such as dibutyltelluronium carbethoxy, phenacyl/ cyano- and carbamoylmethylide (easily prepared by the reaction of dibutyl teUurides with the appropriate substituted methyl hahdes, followed by treatment with a base), undergo Wittig-type olefmation reactions with a variety of carbonyl compounds, giving the expected olefins in satisfactory yields (method A). This behaviour is in sharp contrast to that of stabilized sulphonium yhdes, which are inert towards carbonyl compounds. 

The reaction that occurs with Gly-OEt, 3,5,6-tri-O-methyl-D-glucose, p-toluidine, and phenacyl bromide to give 48 (or its regioisomer) represents a particular case (920PP665). 

Figure 5.1. Variation of half-wave potential (E ) with pH for a-subslituted ketones (a) N-methyl-N-phenacylpiperidinium cation, (b) N-methyl-N-(2-oxopropy )piperidimum cation, (c)diethyl-(phenacyl)-sulphonium cation. Data from refs. (90] and [91].

A, A -Bis(phenacyl)-/i-toluenesulfonamides 173 are readily synthesized by reactions of /(-toluenesulfonamide with phenacyl bromides or/i-toluenesulfonyl chloride with phenacyl amines, and converted into 2,6-diarylpyrazines 174 in high yields by treatment with methyl hydrazinocarboxylate (Equation 27) <1998HAC341>. Another constmction involving cyclization at the final stage by treatment with ammonia was conducted for the synthesis of the framework of a marine alkaloid <2000H(53)15S9>. 

Numerous 2(177)-quinoxalinones and their 1-methyl derivatives were prepared by multistep manipulation starting from anilines <2005H(65)2741>. A considerable interest attaches to reaction of 2,3-furandiones 190 with 1,2-diaminobenzenes to produce 2(l//)-quinoxalinones 191, which can be converted into 3-phenacyl quinoxalinones by alkaline hydrolysis (Scheme 58) <2005H(65)2161>. 

Reactions of the salts 79-81 with chloroacetonitrile, methyl chloroacetate, chloroacetone, or substituted phenacyl bromide yield different products the thiazoles 90 are formed in excellent yield from the reaction with 79 (Equation 1) and when salts 80 and 81 are treated with phenacyl bromide, thiazolopyridine 91 and benzoxazine derivative 92 are formed, respectively <2004H(63)2319>. 

Similarly, 6-methyl-3-phenacyl-l,3-oxazine-2,4(3/f)-diones 110 are transformed... 

The chiral reduction of phenacyl chloride (2) was run using either the methyl- or methoxy- oxazaborolidine (3) as the catalyst. After optimization of the reaction... 

---