4,6 Dimethyl-l,2-pyrone

The fore-run of 30-40 g consists mostly of a mixture of 4,6-dimethyl-l,2-pyrone and ethyl isodehydroacetate. 

Dimethyl-l,2-pyrone, 32, 78 5,5-Dimethyl-2-pyrrolidone, 32, 59 Dimethyl sulfate, 31, 72, 91 Dimethyl cz, v-A4-tetrahydrophthalate,... 

Die von Feist bei der Einwirkung von Alkali auf 3-Brom-4.6-dimethyl-2-pyron-5-carbonsaureathylester (IV) erhaltene Saure, welche fruher als l-Methylcyclopropen-2.3-dicarbonsaure (V) formuliert wurde, ist nach neueren Untersuchungen von Ettlinger (86) die isomere l-Methylencyclopropan-trans-2.3-dicarbonsaure (VI). 

Kato et al,94 reported that 2-amino-6-methylpyridine and diketene did not yield 4-oxo-4/f-pyrido[l,2-a]pyrimidines but instead yielded 2-acetyl-acetamido-6-methylpyridine and pyridone or pyrone derivatives. 2-Methyl-4-oxo-4H-pyrido[l,2-a]pyrimidine (47) and its 8-methyl derivative have also been prepared from 2-aminopyridine and 2-amino-4-methylpyridine with N,N-dimethyl-3-aminocrotonamide95 or with acetoacetamide45 in yields of 5 and 39°,. respectively. 

H-Pyron 4.6-Dimethyl-5-ethoxy-carbonyl- VIII, 629 1,4,9,12-Tetraoxa-dispiro 4.2.4.2]te-tradeca-6,13-dien EI4a/l, 546... 

Linearly Conjugated Dienones. - Two reaction modes have been detected following a study of the photoreactivity of 4,6-dimethyl-oc-pyrone in a matrix. Irradiation with A > 315 nm brings about both ring-opening to yield a ketene and valence isomerization to produce l,5-dimethyl-2-oxa-3-oxobicyclo[2.2.0]-hex-5-ene. ... 

Dimethyl-3-propyl-pyron.(4)(l) 17, 300. 4-Ozo-2-methyl-3-propy. 6-metl Ien-5.6-di<... 

Fused 3-bromo-5-carbethoxy-4,6-dimethyl-2-pyrone added rapidly to boiling 7 M KOH, the flask inclined at an angle of 40° to prevent loss during a violent evolution of alcohol occurring ca. 1 min. after the addition, then boiling continued for 30 min. frans-l-methylenecyclopropane-2,3-dicarboxylic acid. Y ... 

Scheme 6.108 Products ofthe interception of 1,2,4,6-cyclohepta-tetraene (5) with 1,3-diphenylisobenzofuran, anthracenes, 2,5-dimethyl-3,4-diphenylcyclopenta-2,4-dien-l-one, methyl 2-pyrone-5-carboxylate, tropones, 8,8-dicyanoheptafulvene and 1,3,5-cycloheptatrienes.

Dimethyl-y-pyrone reacts with sodium selenide (or sodium hydrogen selenide) to give 2,6-dimethyl-4-seleno-y-pyrone (66). This, in turn, reacts with sodium selenide to give 4,6-bis(hydroseleno)-3,5-heptadien-2-one (67), which is readily oxidized by air to 5-methyl-l,2-diselenol-3-yIidene acetone (68).84,85... 

D, dodecahedron A, square antiprism BCTP, bicapped trigonal prism BCO, bicapped octahedron DTC, N,N-diethyldithiocarbamate HFA, hexafluoroacetylacetonato FOD, l,l>l>2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octane dionato NTA, nitrilotriacetato acac, acetylacetonato PCN, phthalocyaninato DMP, 2,6-dimethyl-4-pyrone BA, benzoyacetonato pip, piperidine DPM, 2,2,6,6-tetramethylheptane-3,5-dionato py, pyridine phen, 1,10-phenanthroline trop, troplonato. 

Diethoxycarbonyl-l,4-dihydropyridine initially gives a mixture of a cyclobutane-type anti-cis and anti-trans photodimer, the former being, on further irradiation, transformed into the cubic dimer (196) by another 1,2-cyclization.283 On irradiation of 2,6-dimethyl-4-pyrone, a trans cubic dimer with the same skeleton as 196 has been obtained.283 Photo dimerization of thianaphthene 1,1-dioxide gave a mixture of the... 

Among seven-coordinate structures, many involve dike-tonate complexes Ln(diket)3 L these generally have either capped-octahedral or capped trigonal prismatic geometry. A considerable number of complexes with neutral donors (e g. thf) of the type LnX3L4 (X = halide, NCS), however, have structures closest to pentagonal bipyramidal, similarly found in the erbium perchlorate complex with 2,6-dimethyl-4-pyrone (Section 3.7.4). 

DIMETHYL-4-OXO-2H-PYRAN-6-CARBOXYLIC ACID n-BUTYLMESITYLOXID OXALATE 2-CARBO-n-BUTOXY-6,6-DIMETHYL-5,6-DIHYDRO-l,4-PYRONE 3,4-DIHYDRO-2,2-DIMETHYL-4-OXO-2H-PYRAN-6-CARBOXYLIC ACID-n-BUTYL ESTER DIHDYROPYR-ONE 0,a-DIMETHYUa -CARBOBUTOXY-DIHYDRO-7-PYRONE 2,2-DIMETHYL-6-CARBOBUTOXY-2,3-DIHYDRO-4-PYRONE ENT 9 INDALONE... 

Dimerization of sulfene yields disulfone 546, whose protons are readily replaced by deuterium, bromine, or trimethylsilyl groups. Sulfone 546 reacts with 2,6-dimethyl-4-pyrone to give an exo-methylene derivative and it may be tetra-methylated. Other disulfones are obtained by oxidation of 1,3-dithietanes with potassium permanganate or chromium trioxide-fuming nitric acid for resistant dithietanes. As mentioned above, peracetic acid oxidizes a disulfoxide, mono-sulfone, or a monosulfone-monosulfoxide to the disulfone 546. 57b,iii3a 2,2,4,4-Tetra(trifluoromethyl)-l,3-dithietane 537 is oxidized only to the monosulfone 547, even with chromium trioxide-hot, fuming nitric acid the disulfone is only... 

Diels-Alder dienes 1-Acetoxybutadiene. Butadiene. Cyclopentadiene. (rans,mins-l,4-Diacetoxybutadiene. 2,5-Di-o-anisyl-3,4-diphenylcyclopentadienone. 5,5-Dimethoxy-l, 2,3,4-tetrachlorocyclopentadienone. 2,3-Dimethylbutadiene. 6,6-Dimethylfulvene (see o-Acetoxy acrylonitrile). 2,4-Dimethyl-l,3-pentadiene (see Diethyl azodicarboxylate). 2,3-Diphenyl-butadiene. 1,3-Diphenylisobenzofurane (see Potassium I-butoxide). rrans,/nus-l,4-Diphenyl-butadiene. 1,3-Diphenylisobenzofurane. Hexachlorocyclopentadiene. Isobenzofurane. l-o-Nitrophenylbutadiene-1,3. Oxepin (see Diazabicyclo[3.4.0]nonene-S). Phenylcyclone. Piperylene. n-Pyrone (see also Methyl vinyl ketone). Tetrachlorocyclopentadienone. Tetra-chlorofurane. Tetraphenylcyclopentadienone. 

By O-acylation with 2-methyl-l,3-dioxolenium fluoroborate, which reacts as O-acetyl ethylene oxide, 2,6-dimethyl-4-pyrone is converted into 4-acetoxy-2,6-dimethylpyrylium fluoroborate133 (24, Y = 0, R = Ac, X = BF4). The alleged compound with this structure which has been obtained from 8 and acetyl fluoroborate134 is, in fact,133 the BFg-complex of the pyrone. 

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