Showing papers on "Pyran published in 1968"

Polymerization of heterocyclic compounds

Abstract: HETEROCYCLIC COMPOUNDS CONTAINING BOTH 5- AND 6-MEMBERED RINGS SUCH AS FURAN, THIOPHENE, PYRROLE, PYRAN, THIOPYRAN, AND PYRIDINE ARE POLYMERIZED BY SUBJECTING THE COMPOUNDS TO ELECTROLYSIS IN THE PRESENCE OF AN ORGANIC SOLVENT, A SPECIFIC EXAMPE BEING THE ELECTROLYSIS OF FURAN IN ACETIC ACID TO FORM POLYFURAN.

7-mercapto-7-deoxylincomycins and process for preparing the same

Abstract: WHICH ON ACYLATION YIELDS COMPOUNDS OF FORMULA I. HYDROPYRAN 2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-SH)-CH(-NH2)-)TETRA- AND HEATING IT WITH HYDROGEN SULFIDE IN AN INERT SOLVENT FOR FORM A COMPOUND OF THE FORMULA: PYRAN 2-(R-S-),3,4,5-TRI(HO-),6-((-CH(-CH3)-NH-)>CH-)TETRAHYDRO- AN INERT SOLVENT IN THE PRESENCE OF AN ACID ACCEPTOR, THE 2-, 3-, AND 4-HYDROXY GROUP MAY BE COVERSED WITH PROTECTIVE GROUPS, TO FORM A NOVEL COMPOUND OF THE FORMULA: HYDROPYRAN 2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-HALO)-CH(-NH2)-)TETRA- ARE PREPARED BY HEATING A COMPOUND OF THE FORMULA: TETRAHYDROPYRAN 2-(R-S-),3,4,5-TRI(HO-),6-(CH3-CH(-SH)-CH(-NH-CO-R4)-) ANTIBACTERIAL COMPOUNDS OF THE FORMULA:

Concerning the mechanism of the addition of ethanesulfenyl chloride to 3,4-dihydro-2H-pyran

Abstract: The nuclear magnetic resonance spectrum, at −40°, of the crude mixture obtained by the reaction of ethanesulfenyl chloride with 3,4-dihydro-2H-pyran at −40° clearly supports the view that the product is trans-2-chloro-3-ethylthiotetrahydropyran. The possibility that there is initial formation of 3-chloro-2-ethylthiotetrahydropyran followed by its rapid rearrangement to 2-chloro-3-ethylthiotetrahydropyran is ruled out because of the stability of 3-chloro-2-ethylthiotetrahydropyran to distillation under vacuum. The latter compound is obtained as a mixture of cis and trans isomers by the reaction of ethyl mercaptan with 5-chloro-3,4-dihydro-2H-pyran in the presence of sulfur dioxide.

6a,10a-trans-6a,7,10,10a-tetrahydrodibenzo (b,d)-pyran production

Abstract: THIS INVENTION IS DIRECTED TO A PROCESS OF PRODUCING 1HYDROXY - 3 - N-AMYL-6,6,9-TRIMETHYL-6A, 10A-TRANS-6A,7,10, 10A - TETRAHYDRODIBENZO (B,D) - PYRAN AND RELATED PYRANS FROM RESORCINOLS WHICH PYRANS POSSESS PSYCHOTOMIMETIC AND ANALGESIC ACTIVITY.

Synthesis and reactions of 7-methylpyrano[4,3-b]pyran-2,5-dione

Abstract: 7-Methylpyrano[4,3-b]pyran-2,5-dione has been synthesised by condensation of triacetic lactone with malic acid in sulphuric acid. Among the by-products isolated are cis- and trans-β-(4-hydroxy-6-methyl-2-oxopyran-3-yl)acrylic acids. The former is believed to be an intermediate leading to the formation of the pyranopyrandione. This pyranopyrandione is converted by hot aqueous sodium hydroxide into α-coccinic acid. Its aromaticity has been demonstrated by the electrophilic substitutions which it undergoes, its high resonance energy, and by its n.m.r. spectrum.

Derivatives of 2h-pyran-3(6h)-ones and preparation thereof

Abstract: THERE ARE DISCLOSED HEREIN 24-HYDROXY-, 24-ACYLOXY-AND 24-ALKOXY-17B,24-EPOXY-21-NORCHOLANE 3,20-DIONE AND 17B,24-EPOXY-19,21-DINORCHOLANE-3,20-DIONE COMPOUNDS AND THEIR CORRESPONDING CHOLANIC ACID Y-LACTONES WITH OPTIONAL DOUBLE BONDS AT POSITIONS 4,5 AND 22,23 AS WELL AS THEIR CORRESPONDING 11-HYDROXY-AND 11-KETO-DERIVATIVES THEREOF. THE COMPOUNDS HAVE ANTIGONADOTROPHIC ACTIVITY AND METHODS FOR THEIR PREPARATION AND USE ARE ALSO DISCLOSED.

The Hydrogenation of Pyran Derivatives. IV. The Skeletal Rearrangement in the Gas-phase Dehydration of Tetrahydropyran-2-methanol

Abstract: The gas-phase dehydration of tetrahydropyran-2-methanol (TPM), prepared by the hydrogenation of the acrolein thermal dimer (3,4-dihyro-2H-pyran-2-carboxaldehyde (AD)), was investigated over various catalysts under atmospheric pressure In this reaction, some of the pyran ring was found to be rearranged rapidly to a seven- or five-membered ring For example, the highly-purified and crystalline η-alumina without any carrier produced cyclopentanecarboxaldehyde (GPA) as the main product in the yield of 71% at 330°C Over the commercial alumina catalyst, considerable amounts of 2,3,4,5-tetrahydrooxepine (THO) and oxepane (OXP) were produced as by-products, though CPA was the main product; in some cases, as much THO and OXP were produced as CPA On the other hand, the use of a dehydrogenation catalyst resulted in THO as the main product and CPA as a by-product; in the case of the use of copper-chromium oxide supported on Kieselguhr, with hydrogen as a carrier gas at 430°C, the yields of THO and CPA were 448% a

Process for modification of cellulose

Abstract: N - Methylol - 3,4 - dihydro - 2H - pyran - 2 - carbonamide carbonamide is prepared by heating a mixture of 3,4 - dihydro - 2H - pyran - 2 - carbonamide, paraformaldehyde and solid sodium hydroxide to 100-115 DEG C. until molten and then stirring and heating the mixture at 85-90 DEG C. for 4 hours and then cooling it, the resulting product being crystallized from methanol, recrystallized from acetone and further recrystallized from methylated spirits. 2 - N - Stearoylaminomethyl - 3,4 - dihydro-2H-pyran is prepared by heating together a mixture of a solution of stearoyl chloride in benzene and a mixture of 2-aminomethyl-3,4-dihydro-2H-pyran and sodium bicarbonate in benzene under reflux, cooling, filtering, distilling the benzene off the filtrate under vacuum and crystallizing the resulting residue from acetone.ALSO:Cellulosic textile materials and paper may be creaseproofed, waterproofed and given a modified handle, and an affinity for acid dyestuffs by reacting them in the presence as catalyst of a acid or substance capable of generating an acid under the reaction conditions used, with a compound containing at least one 3,4-dihydro - 2H - pyranyl radical. The compound may be 3,4 - dihydro - 2H - pyran itself having the formula 2 - aminomethyl - 3,4 - dihydro - 2H - pyran, 2 - NN - dimethylaminomethyl - 3,4 - dihydro - 2H - pyran, 2 - N - stearoyl aminomethyl - 3,4 - dihydro - 2H - pyran, the neopentyl bisester of 3,4 - dihydro - 2H - pyran - 2 - carboxylic acid, benzyl tris - (3,4 dihydro - 2H - pyran - 2 - carboxyethyl) ammonium chloride, quaternary salts of the triethanolamine tris-ester of 3,4 - dihydro - 2H - pyran - 2 - carboxylic acid, an amide derived from a 2 - amino methyl - 3, 4 - dihydro - 2H - pyran and a 3,4 - dihydro - 2H - pyran - 2 - carboxylic acid, or N - methylol - 3,4 - dihydro - 2H - pyran - 2 - carbonamide obtained by the reaction of formaldehyde on 3,4 - dihydro - 2H - pyran - 2 - carbonamide. The material may be impregnated with a solution or dispersion of the 3,4 - dihydro - 2H - pyranyl compound and catalyst in for example water, dried at a temperature not exceeding 120 DEG C and baked at a temperature of 120 DEG -200 DEG C for from 10 seconds to 30 minutes suitable catalysts being ammonium dihydrogen phosphate or ammonium thiocyanate, butanolamine hydrochloride, tartaric, oxalic or maleic acid, zinc chloride or nitrate or magnesium chloride. Alternatively the material may be immersed in a solution or dispersion of the 3,4 - dihydro - 2H - pyranyl compound and a strong acid, e.g. nitric, hydrochloric, phosphoric, sulphuric or trichloro acetic acid, at the ordinary temperature until reaction has taken place or the material may be padded with the solution or dispersion, batched and allowed to stand until reaction has taken place care being taken to ensure that the material does not dry out during this period. The treatment may be combined with the application of a nitrogen resin precondensate, e.g. methylol derivatives of urea, ethylene urea, thiourea, dicyandiamide, amines, amides, carbamates, aminotriazines, urons, ureins, ureides, imidazolidones, pyrimidones and triazones and lower alkyl ethers thereof, or with the application of an aldehyde, e.g. formaldehyde, glyoxal, succindialdehyde or hydroxyadiphaldehyde, Textile materials made from cotton, linen, viscose rayon including polynosic rayons in the form of fibres, rovings, yarns or woven, non-woven or knitted fabrics may be treated. (D1B of Examples 1 and 2).

Novel method of synthesizing 5,6-celluloseen and the preparation of new cellulose derivatives by reaction with its double bonds

Abstract: A LARGE number of methods of modifying cellulose have recently been developed, but there is not one which would enable certain functional groups to be introduced directly into the pyran ring of the cellulose maeromolecule. However it is quite probable that the introduction of the same 'functional groups into the side chain (synthesis of graft copolymers of cellulose) or directly into the ring may variously affect the properties of the resulting cellulose derivative. At the present stage the introduction of new functional groups into the pyran ring and the preparation of new types of cellulose derivatives, in this way, e.g. derivatives with four acetyl groups in the pyran ring can be effected only by using modified cellulose compounds containing a double bond in the pyran ring, i.e. the so-called celluloseen compounds. This product (celluloseen) was used by us as the starting material for the synthesis of new types of cellulose derivatives. There is information in the literature [1-3] describing a method of synthesizing unsaturated cellulose derivatives containing a double bond between 5 and 6 carbon atoms of the elementary unit (5,6-celluloseen); this involves the treatment of cellulose iodotosylate with absolute piperidine to obtain 5,6-celluloseen compounds containing a considerable number of chemically bound piperidine radicals. There is information in the literature regarding certain reactions for converting the double bond in the 5,6-celluloseen molecule: hydration [1-2], and the addition of CHCla, CC14, PC13, HSiG13 [3] and CHaCOOH [4]. More widespread use of celluloseen for various chemical conversions could be made provided that there was a new and more convenient method of synthesizing this product which does not contain chemically bound nitrogen containing groups. The initial products used for the synthesis of 5,6-celluloseen were cellulose iodotosylate obtained by tosylating cotton fluff [5] with subsequent iodization in the usual manner [1], and also cellulose iodonitrate obtained by iodizing