Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1993-12-30
1995-09-19
Chan, Nicky
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
549520, 549518, 549299, C07D40714, C07D40702
Patent
active
054516897
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method of preparing an epoxide (1a) or (1b) shown below: ##STR3## where R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, aralkyl group, a silyl group, and a silyloxy group; the groups may be bonded with each other to form rings in the case where these groups can be bivalent; these groups may be the same or different, may have substituting groups, or may be branched; and each form (isomer) has a structure in which one side of the plane constituted by double bonds, R.sup.1, R.sup.2, R.sup.3 and R.sup.4, is more sterically hindered in comparison with the other side.
The present invention relates to a method of preparing an epoxide, characterized in that the oxirane ring of said epoxide is formed on the more sterically hindered side.
Further, the present invention relates to a method of preparing 1,6:3,4-dianhydro-.beta.-D-talopyranose (1c), as shown below. ##STR4##
BACKGROUND ART
The compounds having oxirane ring (epoxides) are important targets in organic synthesis, since many of them themselves have biologically active. The oxirane ring in epoxide can be easily substituted by other functional groups, and therefore the epoxides are useful substances which can be employed as starting materials or intermediates for organic synthesis.
Synthesis of such epoxides is carried out through the reaction for formation of oxirane rings. The method for formation of an oxirane ring can contain, for example, the following reactions: peroxides; and adjacent to each other.
An example of the reaction (i) is the oxidative addition reaction (prileschajew reaction) by using peracids such as perbenzoic acid, m-chloroperbenzoic acid, and peracetic acid, as shown in equation 1 below, and another example is Scharpless oxidation in which an allyl alcohol is reacted with an appropriate oxidizing agent in the presence of metal catalyst to stereoselectively give an epoxide, as shown in equation 2 below. ##STR5## where R.sup.6, R.sup.7, R.sup.8, and R.sup.9 represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an aralkyl group, a silyl group, and a silyloxy group; the groups may be bonded with each other to form rings in the case where these groups can be bivalent; and these groups may be the same or different, may contain substituting groups, or may be branched. R represents an alkyl group, an aryl group or an acyl group. ##STR6## where R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are defined as above, and Cat. represents a metal complex catalyst containing a metal such as vanadium, molybdenum, or titanium.
An example of the reaction (ii) is that as shown in the following equation 3. More specifically, a diol is introduced to the double bond of olefin to form a trans-isomer. Then, a leaving group is introduced to one of the two hydroxyl groups, and then the other hydroxyl group is subjected to the intramolecular nucleophilic substitution reaction, thereby forming a oxirane. ##STR7## where R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are the same as defined as above; and R.sup.10 is a protecting group for a hydroxyl group, which can be released as R.sup.10 O--, for example, a acyl group.
In the synthesis of an epoxide, the stereochemistry of the oxirane ring introduced to the double bond is important. In a chain (open ring) type olefin, the conversion of the double bond of the olefin to oxirane ring can be formed an epoxide which can produce two possible diols of threo or erythro isomers after the epoxide is hydrolyzed, depending on the direction of approach of an oxidizing agent such as peracids to double bond plane. Also, in the case of a cyclic compound, two possible isomers can be obtained. These isomers can be formed depending on the direction of approach of an oxidizing agent to the ring plane.
Thus,
REFERENCES:
Nathu, Narendra K. et al., The Chemistry of Lauren-1-ene. II* Remote Functionalization Reactions of the Laurenan-2-ols and the 1.beta.H-Laurenan-2-ols, Aust. J. Chem., 1980, vol. 33, pp. 1589-602.
Rehnberg, Nicola et al., Chiral Aldehydes by Ring Contraction of Pento-and Hexopyranoside Epoxides, J. Org. Chem., Feb. 23, 1990, vol. 55, pp. 5467-5476.
Georges, Michael et al., Stereo-and Regiocontrolled Synthesis of Methyl N-Acetyl-.alpha.-D-sibirosaminide, J. Am. Chem. Soc., 1982, vol. 104, pp. 1101-1103.
Chemical Abstracts, vol. 120, No. 3, 17, Jan. 1994, Abstract No. 31041q, Matsumoto, Katsuya et al., "A novel synthesis of 4-deoxy-D-lyxo-hexose (4-deoxy-D-mannose) . . . ".
"A Synthesis of Methyl 4,6-Dideoxy-3-C-methyl-4-(N-Methylacetamido)-.alpha.-D-Altropyranoside, the 3-Epimer of (Methyl N-Acetylsibirosaminide)" to M. Georges et al. Carbohydrate Research, 130, 115-124 (1984).
"D-Mannosan<1,5>.beta.<1,6> or Levomannosan" to A. E. Knauf et al., J. American Chemical Soc., 63, 1447 (1941).
"An Anhydro Derivative of D-Mannosan<1,5>.beta.<1.6>" to Raymond M. Hann et al., J. Am. Chem. Soc., 64, 925 (1942).
"Synthesis of 1,6:3,4-Dianhydro-.beta.-D-Talopyranose from Levoglucosenone: Epoxidaton of Olefin via trans-Iodacetoxylation" to K. Matsumoto et al., Heterocycles, 34, 10, 1935-1947 (1992).
Woodward et al., JACS, 80, 209 (1958).
Ebata Takashi
Kawakami Hiroshi
Koseki Koshi
Matsumoto Katsuya
Matsushita Hajime
Chan Nicky
Japan Tobacco Inc.
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