7-methoxycyclohepta-1,3,5-triene

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: 1-methoxy-1,3,5-cycloheptatriene can be produced from cycloheptatrienyl tetrafluoroborate (I) as described in Conrow K 1963 Organic Synthesis 43, 101. The reaction of (I) with methanol and sodium bicarbonate in water gives 7-methoxy-1,3,5-cycloheptatriene (II), (reference Conrow K1961, J. Am. Chem. Soc. 83,2342). The 1-methoxy-1,3,5-cycloheptriene can be made by the thermal isomerisation of (II) by heating at 150° for 2.5 hours in nitrogen atmosphere in the presence of antioxidants and absence of water, as described by T. NOZOE and K., Takahashi, Bull Chem. Soc. Japan, 38, 665, 1965. Pratt, J. T. Reaction of Cycloheptatriene, PHD Thesis, University of Washington, Seattle, Wash. 1964. as described in Conrow K 1963 Organic Synthesis 43, 101

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: reacting an aqueous solution of cycloheptatrienyl tetrafluoroborate with methanol and sodium bicarbonate to produce 7-methoxycycloheptatriene;

反応条件: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: Phenothiazine (1.4 gm=0.1% by weight of 7-methoxycycloheptatriene) was dissolved in 1381.9 gm of distilled 7-methoxycycloheptatriene. The solution was then heated under nitroen at ambient pressure for 2 hours at 150° C., during which time low-boiling materials were removed by a condenser set for downward distillation. Upon cooling, the residual material weighed 1345.2 grams, representing a crude yield of 97.3% (based on initial 7-methoxy isomer). NMR analysis indicated a product composition of 76 mole % 3-methoxycyclohepta-1,3,5-triene, 12 mole % 1-methoxycyclohepta-1,3,5-triene and 4 mole % unconverted 7-methoxy isomer. The product was of sufficiently good quality to be utilized for conversion to 1-methoxycycloheptatriene without prior distillation. were removed by a condenser set for downward distillation Upon cooling distillation

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: The preferred embodiment of the improved process of this invention involves the use of the above mentioned process modifications of the prior art process, particularly the use of the polymerization inhibitor phenothiazine, with the additional process improvement of heating the 7-methoxycycloheptatriene in the second step of the process to an elevated temperature, e.g., 180° C. at reduced pressure to give a final product 1-methoxycycloheptatriene of increased mole percent yield and purity. More specifically, it has been found that when 7-methoxycycloheptatriene is heated at 180° C. under reduced pressure, a substantial quantity of the order of 80 mole % of 7-isomer is isomerized to 1-methoxycycloheptatriene with complete consumption of the 7-isomer whereas heating at 150° C. (atmosphere pressure), as in the prior art process, yields the 3-methoxycycloheptatriene as a major component with only approximately 12-13 mole % 1-methoxycycloheptatriene product. Subsequent acid catalyzed rearrangement (step 3 of the synthesis) of the product in the preferred process yields a final product containing approximately 92 mole % of the 1-methoxy isomer and a purity of methoxy isomers of 99 mole % versus a yield of 90 mole % 1-methoxy isomer (96% purity of methoxy isomer) obtained when the improved process of this invention utilizes the atmospheric heating at 150° C. of the prior art process.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: An improved multi-step process for synthesizing the liquid irritant 1-methoxycycloheptatriene through the steps of reacting cycloheptatrienyl tetrafluoroborate in aqueous solution with methanol and sodium bicarbonate to produce 7-methoxycycloheptatriene, thermally isomerizing the 7-methoxycycloheptatriene to 3-methoxycycloheptatriene by heating at 150° C. for 2 hours and isomerizing the 3-methoxycycloheptatriene to 1-methoxycycloheptatriene by acid, catalyzed rearrangement employing methanolic hydrogen chloride followed by neutralization with sodium bicarbonate, filtration and fractional distillation to give the final product the improvement comprising the step of utilizing a polymerization/condensation inhibitor to increase the overall yield and purity of the 1-methoxycycloheptatriene product. The overall yield and purity of the product can further be increased through the step of conducting the thermal isomerization of 7-methoxy to 3- and 1-methoxycycloheptatriene at 180° C. under reduced pressure, e.g., by heating in a sealed reactor.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: 1-methoxy-1,3,5-cycloheptatriene can be produced from cycloheptatrienyl tetrafluoroborate (I) as described in Conrow K 1963 Organic Synthesis 43, 101. The reaction of (I) with methanol and sodium bicarbonate in water gives 7-methoxy-1,3,5-cycloheptatriene (II), (reference Conrow K1961, J. Am. Chem. Soc. 83,2342). The 1-methoxy-1,3,5-cycloheptriene can be made by the thermal isomerisation of (II) by heating at 150° for 2.5 hours in nitrogen atmosphere in the presence of antioxidants and absence of water, as described by T. NOZOE and K., Takahashi, Bull Chem. Soc. Japan, 38, 665, 1965. Pratt, J. T. Reaction of Cycloheptatriene, PHD Thesis, University of Washington, Seattle, Wash. 1964. as described in Conrow K 1963 Organic Synthesis 43, 101