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1.
3,4-Dihydro-2-methoxy-5-methyl-2H-pyran and 3,4-dihydro-2-methoxy-5,6-dimethyl-2H-pyran undergo addition-rearrangement reactions with arylsulfonyl isocyanates to generate the corresponding 3-formyl- and 3-acetyl-6-methoxy-3-methyl-1-(arylsulfonyl)-2-piperidones. For example, 3,4-dihydro-2-methoxy-5-methyl-2H-pyran and phenylsulfonyl isocyanate afforded 3-formyl-6-methoxy-3-methyl-1-(phenylsulfonyl)-2-piperidone as a separable trans/cis mixture in high yield. The more reactive phenoxysulfonyl and alkoxysulfonyl isocyanates provided analogous results. 相似文献
2.
U. G. Ubatullin T. F. Petrushina Yu. N. Popov R. R. Gataullin M. G. Safarov 《Chemistry of Heterocyclic Compounds》1987,23(4):375-376
2-Methyl-5,6-dihydro-2H-pyran reacts with the Simmons-Smith reagent to give a mixture of 2-ethyl-5,6-dihydro-2H-pyran, cis- and trans-2-methyl-3-oxabicyclo-[4.1.0]heptanes, and 2-methyl-2,5,6,7- or 3-methyl-2,3,6,7-tetrahydrooxepine in a ratio of 2251.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 449–450, April, 1987. 相似文献
3.
A. A. Gevorkyan A. S. Arakelyan A. I. Dvoryanchikov 《Chemistry of Heterocyclic Compounds》1986,22(4):380-386
A convenient method has been developed for the synthesis of 4-methyl-2,3,4-trichlorotetrahydropyran by the chlorination of 4-methyl-4-chlorotetrahydropyran, 4-methyl-5,6-dihydro-2H-pyran and its dichloride. A study was carried out on the reactions of 4-methyl-2,3,4-trichlorotetrahydropyran with alcohols, with sodium thiocyanate and Grignard reagents. PMR spectroscopy was used to study the stereochemistry of 4-methyl-2,3,4-trichlorotetrahydropyran and its derivatives, 2-substituted 4-methyl-3,4-dichlorotetrahydropyrans. The dechlorination of these dichloro derivatives by metallic sodium leads to 2,4-disubstituted 5,6-dihydro-2H-pyrans with high regioselectivity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 465–471, April, 1986. 相似文献
4.
[reaction: see text] Ruthenium complex-catalyzed carbonylation of allenyl alcohols quantitatively gave cyclic carbonyl compounds, gamma- and delta-lactones, in which the hydroxy group of allenyl alcohols participated in the cyclization. A wide variety of allenyl alcohols, such as mono-, di-, and trisubstituted alcohols, can be used in this reaction to produce 3- and 4-substituted gamma-lactones. Similarly, the cyclic carbonylation of 3,4-pentadien-1-ol 10a and 2-methyl-4,5-hexadien-2-ol 11a gave delta-lactones, 5,6-dihydro-3-methyl-2H-pyran-2-one 10b, and 5,6-dihydro-6,6-dimethyl-3-methyl-2H-pyran. 2-one 11b, respectively, in a quantitative yield. 相似文献
5.
U. G. Ibatullin T. F. Petrushina R. R. Gataullin M. G. Safarov G. A. Tolstikov 《Russian Chemical Bulletin》1987,36(10):2112-2114
Conclusions Formation of the addition and insertion products upon reaction of 2-methyl-5,6-dihydro-2H-pyran with dihalocarbenes proceeds through a common intermediate which is the result of coordination of the carbene by the heteroatom. This explains the independence of the ratio of addition and insertion products on the reaction conditions and method of generation of the carbenes.Translated from Izvestiya Akademii Nauk SSSR, Vol. 23, No. 10, pp. 2280–2282, October, 1987. 相似文献
6.
3-Nitro-5,6-dihydro-4H-pyran reacts with primary aliphatic and benzylic Grignard reagents and, in suitable hydrolysis conditions, gives the corresponding 2-alkyltetrahydropyran-3-ones in satisfactory yields. 相似文献
7.
Man Jung Han Nam Shik Cho Tae Joon Cho Ji Young Chang 《Journal of polymer science. Part A, Polymer chemistry》1995,33(11):1829-1839
2-Amino-6-chloropurine was reacted with 2-(tosyloxymethyl)-2,3-dihydro-2H-pyran to give 2-(2-amino-6-chloropurin-9-ylmethyl)-2,3-dihydro-2H-pyran ( 3 ) and its N7-isomer ( 4 ), which were treated with 5% aqueous trimethylamine to result in 2-(guanin-9-ylmethyl)-2,3-dihydro-2H-pyran ( 5 ) and its N7-isomer ( 6 ), respectively. 2-(N2-Acetylguanin-9-yl-methyl)-3,4-dihydro-2H-pyran ( 7 ) and 2-(N2-acetylguanin-7-ylmethyl)-3,4-dihydro-2H-pyran ( 8 ), obtained by acetylation of compounds 5 and 6 , were copolymerized with maleic anhydride to give the alternating copolymers 9 and 10 , and they were hydrolyzed to result in poly[ {2-(guanin-9-ylmethyl)tetrahydropyran-5,6-diyl} {1,2-dicarboxyethylene}] ( 11 ) and poly[ {2-(guanin-7-ylmethyl)tetrahydropyran-5,6-diyl} {1,2-dicarboxyethylene}] ( 12 ), re-spectively. Polymer 11 showed hypochromicity whereas 12 exhibited hyperchromicity in aqueous solutions. Polymers 11 and 12 in aqueous solutions showed very strong excimer fluorescence with the maximum intensities at 432 and 446 nm, respectively, at room tem-perature. The two polymers showed polyelectrolyte effects, e.g., very high GPC molecular weights as well as reduced viscosities at low concentrations in water. Normal behavior was retained by addition of inorganic salts. Sodium salts of polymers 11 and 12 migrated to the anode by electrophoresis and both showed two bands. © 1995 John Wiley & Sons, Inc. 相似文献
8.
L. A. Ignatova A. E. Gekhman P. L. Ovechkin B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1974,10(3):307-309
3,4,4,6-Tetramethyl-2-aryliminotetrahydro-1,3-oxazines were synthesized by intramolecular cyclization of N-aryl-N′-methyl-N′-(2-methyl-4-hydroxy-2-pentyl)-S-methylisothioureas. 4,4,6-Trimethyl-2-(N-methyl-N-arylamino)-5,6-dihydro-4H-1,3-oxazines were obtained by methylation of 4,4,6-trimethyl-2-arylamino-5,6-dihydro-4H-1,3-oxazines. 相似文献
9.
P. L. Ovechkin L. A. Ignatova A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1974,10(3):310-312
N-Aryl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas are cyclized in acidic media to 4,4,6-trimethyl-2-arylimino-5,6-dihydro-4H-1,3-thiazines, the methylation of which with methyl iodide gives 4,4,6-trimethyl-2-methylarylamino-5,6-dihydro-4H-1,3-thiazines. 3,4,4,6-Tetramethyl-2-aryliminotetrahydro-1,3-thiazines were synthesized by cyclization of Naryl-N′-methyl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas. 相似文献
10.
The use of hindered trialkylaluminum reagents is found to result in stereoselective reduction of the carbonyl group of 2-propionyl-6-methyl-3, 4-dihydro-2H-pyran. 相似文献
11.
Stanislav A. Grabovskiy Yuri I. MurinovNatalia N. Kabal’nova 《Tetrahedron letters》2012,53(45):6025-6028
Dehydration of 5,6-dihydro-5,6-dihydroxy-6-methyl- and 5,6-dihydro-5,6-dihydroxy-1,3,6-trimethyl-uracil in 0.4 M aqueous sulfuric acid gives 5-hydroxy-6-methyl- and 5-hydroxy-1,3,6-trimethyluracil in quantitative yields. Two possible mechanisms have been examined using the mPW1k/6-311+G(2df,2pd)//mPW1k/6-31+G(d,p) method for the transformation of methylated and non-methylated 5,6-dihydro-5,6-dihydroxy-6-methyluracils into the corresponding 5-hydroxy-6-methyluracils. The first is a hydride C5-C6 shift occurring in concert with the loss of a water molecule and formation of the corresponding protonated 5,6-dihydro-5-oxo-6-methyluracils. The second is an acid-catalyzed dehydration reaction to yield 5-hydroxy-6-methyluracils. The calculations demonstrated that the second pathway was energetically most favorable. 相似文献
12.
M. S. Sargsyan S. A. Mkrtumyan A. A. Gevorkyan 《Chemistry of Heterocyclic Compounds》1987,23(3):253-256
The reaction of 4-methyl-5,6-dihydro-2H-pyran with acetyl nitrate to give additive and substitutive nitration products has been examined. It is shown that the addition product, 4-acetoxy-4-methyl-3-nitro-tetrahydropyran, is deacylated on treatment with bases to give an ,-unsaturated nitro-compound which isomerizes under the reaction conditions to a ,-unsaturated nitro-compound. 4-Acetoxy-4-nitromethyltetrahydropyran behaves similarly.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 305–308, March, 1987. 相似文献
13.
L. A. Ignatova P. L. Ovechkin M. Z. Branzburg A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1972,8(8):939-942
4,4,6-Trimethyl-2-alkyl(aryl)amino-5,6-dihydro-4H-1,3-oxazines were synthesized via two methods: amination of 4,4,6-trimetiiyl-2-methylthio-5,6-dihydro-4H-1,3-oxazine and cyclization of N-aryl-N-(2-methyl-4-hydroxy-2-amyl)-S-methylisothiourea.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1037–1040, August, 1972. 相似文献
14.
In the electron impact induced fragmentation of 2,3-disubstituted 5,6-dihydro-1,4-oxathiines, the cleavage of the heterocyclic ring proceeds through the retro Diels-Alder type of reaction. The further fragmentation of the resulting radical cation gives rise to substituted carbonyl or thiocarbonyl cations. This fragmentation favours the formation of an ion which, in the electron-deficient carbon-oxygen or carbon-sulphur triple bond, is stabilized by an electron-releasing group. The ring fragmentation was observed to be dependent on the nature of the 3-substituent of the ring when a series of 3-substituted 5,6-dihydro-2-methyl-1,4-oxathiines was investigated. 相似文献
15.
The main objectives of the present work were the synthesis of the two cis diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine and the kinetic study of their hydrolytic deamination. The preparation of the two glycols, two main (*)OH-mediated oxidation products of 5-methyl-2'-deoxycytidine, was achieved in two steps. The first one involved the synthesis of the two trans-(5R,6S)- and (5S,6R)-5-bromo-6-hydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine. In a subsequent step, the bromohydrins were specifically converted into the cis-(5S,6S) and (5R,6R) diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine, respectively, under slightly alkaline conditions. The resulting glycols were purified by reverse phase high performance liquid chromatography and characterized by extensive spectroscopy measurements including (13)C- and (1)H-NMR analyses. Exact mass determination was inferred from high resolution fast atom bombardment mass spectrometry measurements. Circular dichroism spectroscopy confirmed the diastereomeric relationship existing between the pair of glycols. Kinetic study of the deamination of the above glycols was carried out in phosphate buffer solutions (pH 7) at two different temperatures (37 degrees C and 25 degrees C) in order to determine the thermodynamic and kinetic parameters of the reaction. 相似文献
16.
2-Methoxy-6-ethoxy-5-cyano-3,4-dihydro-2H-pyran ( 1 a), 2-isobutoxy-6ethoxy-5-cyano-3,4-dihydro-2H-pyran ( 1 b), and 2,6-diethoxy-3-methyl-5-cyano-3,4-dihydro-2H-pyran ( 1 c) were prepared by (4 + 2) cycloaddition reaction of ethyl α-cyanoacrylate with the corresponding vinyl ethers. Compounds 1 a-c were ring-open polymerized by cationic catalyst to obtain alternating head-to-head (H? H) copolymers. For comparison, head-to-tail (H? T) copolymer 3 a was also prepared by free radical copolymerization of the mixture of the corresponding monomers. The H–H copolymer exhibited minor differences in its 1H-NMR and IR spectra, but in the 13C-NMR spectrum significant differences were shown between the H? H and H? T copolymers. Glass transition temperature (Tg) of H? H copolymer was higher than that of the corresponding H? T copolymer, but thermal decomposition temperature of the H? H copolymer was lower than that of the H? T copolymer. Compounds 1 a and 1 b copolymerized well with styrene by cationic catalyst, but compound 1 c failed to copolmerize with styrene. All of the H-H and H-T copolymers were soluble in common solvents and the inherent viscosities were in the range 0.2–0.5 g/dL. 相似文献
17.
Basavaiah D Rao JS Reddy RJ Rao AJ 《Chemical communications (Cambridge, England)》2005,(20):2621-2623
An atom-economical stereoselective synthesis of [{1-acetyl-5-methyl-6,8-dioxabicyclo(3.2.1)octane}-7-spiro-3'-(indolin-2'-one)] derivatives, containing both the oxindole and 6,8-dioxabicyclo(3.2.1)octane moieties via TiCl(4) catalyzed coupling of 2-acetyl-6-methyl-2,3-dihydro-4H-pyran with isatin derivatives is described. 相似文献
18.
I. N. Bazhitova Kh. F. Sagitdinova U. G. Ibatullin M. G. Safarov 《Chemistry of Heterocyclic Compounds》1992,28(3):269-272
Thioureas, chloroacetamides, and 4-thiazolinone and 2-aminothiazole derivatives were obtained from 4-methyl-5-(R-amino)-5,6-dihydro-2H-pyrans and 4-(R-aminomethyl)-5,6-dihydro-2H-pyrans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 323–326, March, 1992. 相似文献
19.
Kh. F. Sagitdinova U. G. Ibatullin Z. R. Gallyamova G. A. Rakhmatullina N. A. Akmanova M. G. Safarov 《Chemistry of Heterocyclic Compounds》1990,26(8):932-935
N-(Benzylidene)- and N-(2-phenylamino-2-oxoethylidene)aniline N-oxides add stereospecifically to the double bond in 4-methylene- and 4-acryloylamino-4-methyltetrahydropyrans to give substituted isoxazolidines. The use of 4-methyl-5-arylamino- and 4-arylaminomethyl-5,6-dihydro-2H-pyrans for the synthesis of novel N-oxides has given tricyclic adducts resulting from intramolecular cyclization of the required compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1113–1116, August, 1990. 相似文献
20.
A. S. Kukharev I. G. Tishchenko V. I. Tyvorskii 《Chemistry of Heterocyclic Compounds》1987,23(10):1049-1055
4-Aminomethyl-2-buten-4-olides, 5-hydroxy-5,6-dihydro-2-pyridone, and isomeric 8,9-dihydro-4-cyano-2-oxofuro[2,3-c]piperidines were obtained by the base-catalyzed cyclization of 5-amino-4-hydroxy-4-alkyl-2-pentenoic acid esters. 5-Di-methylamino-3-methyl-4-oxovaleric acid ester and 4-dimethylamino-2-buten-4-olide, respectively, were isolated by isomerization of 5-dimethylamino-3-methyl-4-hydroxy-2-pentenoic acid ester and 4-dimethylamino-2-penten-5-olide in the presence of sodium isopropoxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1313–1319, October, 1987. 相似文献