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Please login to access the full content or check if you have access via17.8.1.1.3.2.1 Variation 1: 1,19-Dimethyl-b-bilenes
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Smith, K. M.; Vicente, M. G. H., Science of Synthesis, (2004) 17, 1106.
1,19-Dimethyl-b-bilenes can be prepared by two general methods (Scheme 25). The first is suited to the synthesis of fully alkylated bilenes, but gives low yields when bilenes bearing electron-withdrawing substituents are required; condensation of 2 equivalents of a 2,3,4-trialkyl-1H-pyrrole (e.g., 74) with one of a 1,9-bis(methoxymethyl)dipyrromethene 111 affords a b-bilene salt 112, which is usually symmetrical about the 10-carbon atom.[70–73] Better is the route in which a 1-formyldipyrromethane 113 is treated with a 1-unsubstituted dipyrromethane (or with the corresponding 1-carboxylic acid) 114;[74] in this way unsymmetrically substituted b-bilenes 115 can be obtained in high yield, but it is advisable[75] to have an electronegative group on the terminal rings of the b-bilene in order to prevent acid-promoted side reactions which result in mixtures of porphyrins.
Meeeee 88 Meeeeeeee ee 8,88-Meeeeeee-e-eeeeeee[88–88]
Meeeeeeeeeee Meeeeeeeee
8,88-Meeeeee-8,8,8,8,88,88,88,88-eeeeeeeeee-e-eeeeee Meeeeeeeeeee (888); Meeeeee Meeeeeeee:[88]
8,8-Meeeeee-8,8-eee(eeeeeeeeeeeee)-8,8-eeeeeeeeeeeeeeeeeeeeee eeeeeeeeeeee (888; 8.8 e, 8.88 eeee) ee eeeeeee (88 eM) (MMMMMMM: eeeeeeeeee) eee 8,8,8-eeeeeeeee-8M-eeeeeee (88; 8.8 e, 88.88 eeee) eeee eeeeeeee eee 88 eee. Mee eeeeeeeee eeeee (88 eM) eee eeee eeeee eee eee eeee eee eeeeee. Mee eeeeeeeeeeee eeeeeeeeeeee, eee eeeeee eeee eeeeeeeee eeeee, eee eee eeee eeeeeeeeeeeeee (MMMe8/eeeeeeeee eeeee) ee eeee 888; eeeee: 8.8 e (88%); ee 888°M (eee).
8,88-Meeeeeee-8,8,8,8,88,88,88,88-eeeeeeeeee-e-eeeeee (888); Meeeeee Meeeeeeee:[88]
M eeee ee 8-eeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeeeeeeeee-8-eeeeeeeeee eeee (888 M8 = MM8M; 8 e, 8.88 eeee) eee 8-eeeeee-8-eeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeeeeeeeee (888; 8 e, 8.88 eeee) ee MMM (8 eM) eee eeeee ee MeMM (88 eM). Mee eeeeeee eee eeeeeee eee 88 eee, e eeee ee MMe ee MeMM (88%, 8 eM) eee eeeee eeeeeeee, eee eee eeeeeeeeeee (888·MMe) eee eeeeeeeee ee eeeeeeeeee eeeee 8 e eee eeeeee eeee MeMM. M eeeeeee ee eee eeeeeee eee eeeeeeeee ee MMMe8 eee eeeeeee eeee ee eeeeee ee Me8M. Mee eeeeeee eeeeeeee ee eeeeeeeeeeeee ee eee eeee eee eeeeeeeeeeee (eeeeeeee/MMMe8) ee eeee eee e-eeeeee 888 ee eeeeee eeeeeee; ee 888°M (eee).
References
[70] | Meeeeee, M.; Meeeeeeee, M., M. Meeeeee. Meee., (8888), 888, 888. |
[71] | Meeeeee, M. M.; Mee, M. M., M. Meee. Mee., (8888), 8888. |
[72] | Meeeee, M. M.; Meeee, M.; Meeeeee, M. M.; Meeeeee, M.; Meeeeeeeee, M.; eee eee Meeee, M., M. Meee. Mee. M, (8888), 888. |
[73] | Meeeee, M. M.; Meeeee, M. M. M.; Meeee, M. M., Meee. M. Meee., (8888) 88, 8888. |
[74] | Meeee, M. M.; Meeee, M. M., Meee. M. Meee., (8888) 88, 8888. |
[75] | Meeeee, M. M.; Meee, M. M.; Meeeeeee, M. M.; Meeeeee, M. M.; Meeee, M. M.; Meeeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 888. |