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    • 32. 发明授权
    • 3,4,-dihydro-2H-pyrans
    • 3,4, - 二氢-2H-吡喃
    • US4845247A
    • 1989-07-04
    • US76612
    • 1987-07-23
    • Wolfgang SpieglerNorbert GoetzManfred SauerwaldToni DocknerRolf Fischer
    • Wolfgang SpieglerNorbert GoetzManfred SauerwaldToni DocknerRolf Fischer
    • C07D309/22C07D309/28C07D309/32
    • C07D309/32C07D309/22C07D309/28
    • 3,4-dihydro-2H-pyrans I ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each H or C.sub.1 -C.sub.6 -alkyl and R.sup.3 is not C.sub.2 -C.sub.4 -alkyl when A is COOR.sup.5 and A is COOR.sup.5, .dbd.CHOR.sup.5, in which R.sup.5 is C.sub.1 -C.sub.4 -alkyl, or CH.sub.2 OR.sup.6, in which R.sup.6 is C.sub.1 -C.sub.4 -alkyl or is benzyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, alkoxy or halogen, or is formyl, C.sub.2 -C.sub.4 -alkylcarbonyl or benzoyl which is unsubstituted or substituted by C.sub.1 -C.sub.4 -alkyl, alkoxy or halogen, are prepared by eliminating an alcohol from a 2-alkoxytetrahydropyran II ##STR2## where R.sup.7 is C.sub.1 -C.sub.18 -alkyl and A' is COOR.sup.5, CH(OR.sup.5).sub.2 or CH.sub.2 OR.sup.6, in which R.sup.5 and R.sup.6 have the meanings stated for I, the elimination being carried out by passing II, in the liquid or gaseous state, into a high boiling mineral oil at above the boiling point of the resulting dihydropyran I, removing I in gaseous form, replenishisng the high boiling mineral oil when it becomes enriched with byproducts, and removing the said mineral oil enriched with byproducts.
    • 3,4-二氢-2H-吡喃酮其中R 1,R 2,R 3和R 4各自是H或C 1 -C 6烷基,当A是COOR 5 + L时,R 3不是C 2 -C 4 - 烷基,A是 COOR 5 = CHOR 5,其中R 5是C 1 -C 4 - 烷基或CH 2 OR 6,其中R 6是C 1 -C 4烷基或是未被取代或被C 1 -C 4 - 烷基,烷氧基或卤素取代的苄基,或是甲酰基, 未取代或被C 1 -C 4 - 烷基,烷氧基或卤素取代的C 2 -C 4 - 烷基羰基或苯甲酰基通过从2-烷氧基四氢吡喃II中除去醇来制备,其中R 7是C 1 -C 18烷基和A' 是COOR 5,CH(OR 5)2或CH 2 OR 6,其中R 5和R 6具有I所述的含义,通过使II在液体或气态下进行的消除在高于沸点的高沸点矿物油中进行 的所得二氢吡喃I,除去气体形式的I,当富含副产物时补充高沸点矿物油,并除去富含副产物的所述矿物油。