Reference of 5876-51-7,Some common heterocyclic compound, 5876-51-7, name is 5-Iodobenzo[d][1,3]dioxole, molecular formula is C7H5IO2, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
[00230] To 27.7 mg PdCl2(dppf).CH2Cl2 in a reaction tube under nitrogen were added 4 ml dioxane, 0.14 ml (1.0 mmol) of 2,6-dimethylpiperidine, 0.23 ml (1.5 mmol) pinacolborane (crimson solution) and 261 mg (1.05 mmol) 1-iodo-3,4-methylenedioxybenzene. The crimson reaction solution was warmed to 80 C. with stirring in an oil bath. Analysis of the reaction solution by gc, as described above, was carried out at intervals (see Table 19.1). The reaction is fast and is complete after 4 h reaction time. The initial reaction rate with 1 mmol of 2,6-dimethylpiperidine as base exceeds that found using 3 mmol of triethylamine (see Table 17.3; catalyst not activated prior to reaction) and the final product distribution is essentially the same. This is not the case if one compares the reactions in which either 1 mmol of 2,6-dimethylpiperidine or 1 mmol of triethylamine is used as base. As noted above, dehalogenation in reactions using 1 mmol of triethylamine is considerable (23% of peak area in the gc is due to 1,3-benzodioxole) and the desired product, the pinacol ester of 3,4-methylenedioxyphenylboronic acid is only 69% of peak area. [00231] The results are different when 3 mmol of 2,6-dimethylpiperidine is used in the reaction. The reaction rate is reduced, especially after the first 1 to 2 hours (see Table 19.2). The results suggest that in situ catalyst activation may be initially enhanced using 2,6-dimethylpiperidine but excess of this base also retards the reaction. Dehalogenation occurs predominantly during the earlier part of the reaction. [TABLE-US-00007] TABLE 19.1 Rate of product formation on reaction of 1-iodo-3,4-methylenedioxybenzene with pinacolborane at 80 C., catalyst PdCl2(dppf).CH2Cl2, base 2,6-dimethylpiperidine (1.0 mmol). The concentrations are expressed in area % (uncorrected for response factors) determined by gc analysis of aliquots of the reaction solution taken at selected reaction times*. Reaction Time (h) [C00047] [C00048] [C00049] [C00050] 1 8.7 2 70 20 2 8.4 4.3 42 44 3 8.5 6.2 16 67 4 11.5 6.5 0.3 80 5 11.6 6.4 0 80 *The reaction was quenched at the selected reaction time by addition of the aliquot of reaction solution to a water/ethyl acetate mixture. [TABLE-US-00008] TABLE 19.2 Rate of product formation on reaction of 1-iodo-3,4-methylenedioxybenzene with pinacolborane at 80 C., catalyst PdCl2(dppf).CH2Cl2, base 2,6-dimethylpiperidine (3.0 mmol). The concentrations are expressed in area % (uncorrected for response factors) determined by gc analysis of aliquots of the reaction solution taken at selected reaction times*. Reaction Time (h) [C00051] [C00052] [C00053] [C00054] 1 8.9 1.3 69 20 2 9.2 2.8 49 38 3 9.6 3.5 33 53 4 11 5.1 25 58 5 10 5.6 18 66 6 10 5.9 13 71 25.5 12 6.1 2.2 78 *The reaction was quenched at the selected reaction time by addition of the aliquot of reaction solution to a water/ethyl acetate mixture.
These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 5-Iodobenzo[d][1,3]dioxole, its application will become more common.
Reference:
Patent; Commonwealth Scientific and Industrial Research Organisation; US6680401; (2004); B1;,
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com