The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Heterocyclic vinyl eters. XVI. 2,5 Dimethyl-1,4-dithiadiene》. Authors are Parham, William E.; Mayo, Gwendolyn L. O.; Gadsby, Brian.The article about the compound:2-Bromopriopionaldehydediethylacetalcas:3400-55-3,SMILESS:CC(Br)C(OCC)OCC).Synthetic Route of C7H15BrO2. Through the article, more information about this compound (cas:3400-55-3) is conveyed.
cf. C.A. 53, 17133b. 2,5-Dimethyl-1,4-dithiadiene (I), the 1st example of an alkyl dithiadiene, was prepared Na2S.9H2O (559 g.) in 2800 cc. boiling 95% EtOH and 149 g. S refluxed 10 min., treated with 654 g. MeCHBrCH(OEt)2 at such a rate as to maintain reflux, refluxed 3 hrs., 500 cc. solvent removed, treated with 135 g. NaHCO3, distilled to collect 2.1 l. solvent, cooled, diluted with 1500 cc. H2O, and extracted with Et2O, the extract evaporated, and the residue kept in vacuo to constant weight gave 525-50 g. black oily residue, n26D 1.50; a 538-g. portion in 500 cc. dry Et2O diluted with 5 l. liquid NH3, treated with 200 g. Na during 1 hr. and then with 500 cc. liquid NH3, stirred 30-40 min., treated with 200 g. NH4Cl in small portions, and evaporated with stirring, the gummy residue kept at 32° overnight, stirred with 1 l. iced H2O, adjusted with concentrated HCl to pH 8-8.5 and then with CO2 to pH 7.8-8.0, the aqueous layer extracted with Et2O, and the combined organic layer and Et2O extract worked up gave 300 g. MeCH(SH)CH(OEt)2 (II), b9 60-78°, n27D 1.436-1.437. II (1.5 g.), NaOEt from 0.23 g. Na in 10 cc. EtOH, and 1.5 cc. BuBr refluxed 1.5 hrs., acidified with concentrated HCl, and treated with 2,4-(O2N)2C6H3NHNH2 gave 2,4-(O2N)2C6H3NHN:CHCH(SBu)Me, 110-11° (95% EtOH). p-MeC6H4SO3H.H2O (1.0 g.) in C6H6 dried azeotropically, treated with 49.2 g. II, refluxed 2 hrs., cooled, washed, dried, and distilled yielded 26.2 g. semisolid mixed isomers of 2,5-dimethyl-3,6-diethoxy-1,4-dithiane (III), b0.35 82-7°, n25D 1.5012; the solid portion of the mixture recrystallized from 95% EtOH gave the α-isomer, cubes, m. 119-20°. Powd. KMnO4 (47.4 g.) added in small portions to 23.6 g. mixed isomeric III in 162 g. glacial AcOH, the mixture kept 3 days at room temperature, the AcOH distilled the residue diluted with 160 cc. H2O, treated with SO2, and filtered, the tarry, yellow, semisolid residue dried in vacuo and extracted with EtOAc in a Soxhlet apparatus, and the extract worked up gave 5.22 g. tetroxide of III, needles, m. 190-1° (absolute EtOH). III (12.00 g.) and 0.1 g. P2O5 heated at 160°, 1.93 g. EtOH removed during 2 hrs., the residue cooled and diluted with Et2O, and the Et2O solution worked up gave 4.24 g. 3-ethoxy-2,5-dimethyl-1,4-dithi-5-ene (IV), b5.3 104-5°, b0.25 60-2°, n26.5D 1.5437. The solid isomeric III (3.66 g.) gave 1.03 g. IV. Al2O3 pellets (60 g.) heated 40-8 hrs. at 260° in a vertical tube under N, cooled to 213°, 5 cc. absolute EtOH passed at 10-12 drops/min. with about 0.5 l. N/min. through the tube, 30 g. III in 25 cc. absolute EtOH added at the same rate and finally 10 cc. absolute EtOH, and the pyrolyzate condensed in a Dry Ice trap, washed with 2% aqueous NaOH and saturated aqueous NaCl, dried, and distilled yielded 6.9 g. I, b2.8 72-8°, n25D 1.56, and 8.2 g. IV, b2.0 91-106°, n26.5D 1.5329-1.5258. Similar pyrolytic runs on Al2O3, conditioned at 316-60° with a N flow of 0.3-0.5 l./min., at 204-310° gave yields of I and IV varying from 0-38 and 0-64%, resp.; at temperatures above 270° neither I nor IV were obtained. I (about 5 g.) in 1:1 Et2O-petr. ether chromatographed on Al2O3 gave pure I, pale yellow oil, b2.0 61-2°, n26D 1.5754. IV purified similarly gave an almost colorless oil, b2.4 90-2.5°, n26.9D 1.5383. IV (22.5 g.) passed at 227° over 60 g. Al2O3 pellets (conditioned at 360°) gave 7.1 g. unchanged IV, n26D 1.534, and 5.0 g. I, n26D 1.568. I (0.400 g.) in glacial AcOH treated at 70° with 2.5 cc. 30% H2O2 during 1.5 hrs., kept 18 hrs. at 70° and 1 hr. at 10°, and filtered from 0.35 g. product, the filtrate evaporated to dryness, the residue dissolved in 2 cc. glacial AcOH, treated with a few drops 30% H2O2, heated 0.5 hr. on the steam bath, and filtered, and the combined residues (0.57 g.) recrystallized from 95% EtOH gave tetroxide of I, m. 218-21° with sublimation. I (4.35 g.), b2.3 62-4°, n27.3D 1.5702, refluxed under a stream of N 1 hr. gave 0.88 g. 2,4-dimethylthiophene (V), n27.8D 1.5057, b. 90-138°, the residue distilled yielded 0.27 g. liquid, b2 55°, n27D 1.5218, and 2.13 g. black residue. V (0.75 g.) in 1.0 cc. C6H6 and 1.36 g. Ac2O treated at 60° with 4 drops 85% H2PO4, refluxed 2.5 hrs., cooled, diluted with 2.5 cc. H2O, kept overnight, and extracted with Et2O, the extract washed, dried, and evaporated, the residue refluxed 2 hrs. with 1 g. NH2OH.HCl, 5 cc. C5H5N, and 5 cc. absolute EtOH and evaporated at room temperature in vacuo, the residual oil triturated with 5 cc. H2O, and the resulting solid recrystallized from 95% EtOH gave a mixture, m. 55-68°, of a material, m. about 65°, and a material, m. about 120°, which could not be separated chromatographically; the mixture kept 14 days at room temperature in a sublimation apparatus gave a small amount of oxime of V, m. 118-23° (aqueous EtOH). p-MeC6H4SO3H (0.2 g.), 44.0 g. BuOH, and 12.0 g. IV refluxed 24 hrs., cooled, diluted with 150 cc. Et2O, and worked up gave 2.5 g. unchanged IV, and 7.3 g. 3-butoxy-2,5-dimethyl-1,4-dithi-5-ene, pale yellow oil, b0.45 81-91°, n28D 1.52; it reacted rapidly with O. I (1.89 g.) in 15 cc. petr. ether treated rapidly with 1.75 g. AlCl3, diluted with H2O, and stirred overnight, and the gray tarry precipitate triturated with 95% EtOH left a gray solid, (C6H8S2)x, m. 140-50°, insoluble in EtOH and Et2O. I (1.48 g.) in 125 cc. Ac2O treated with 1.3 cc. nitrating solution gave 0.30 g. amorphous brown solid. I (3.2 g.) in 25 cc. CCl4 treated at 0° with 1.6 g. Cl gave a CHCl3-insoluble black tar, and a CHCl3-soluble oil, b2.2 70° to b0.2 80°, which rapidly decomposed to a black tar and HCl. I (1.40 g.) in 130 cc. Ac2O treated with 1.6 g. Br gave 0.36 g. brown amorphous solid, m. 40-70° (the solid contained Br but decomposed upon attempted recrystallization), and 0.95 g. unidentified Et2O-soluble oil which gave no solid on oxidation with H2O2 in AcOH at 70°. I (1.5 g.), 1.4 g. Ac2O, and 2 drops 85% H3PO4 heated at 100° yielded 0.6 g. unchanged I and 0.22 g. orange oil, n25D 1.5850, which showed a CO absorption. I (1.00 g.) and a solution prepared from 58 g. HgCl2, 12 g. 33% aqueous NaOAc, and 54 g. 95% EtOH gave 1.35 g. solid, m. 100-30°, which digested with hot EtOH and filtered hot gave a solid, m. 85-100° (EtOH). Similar runs in the absence of NaOAc gave impure amorphous solids, m. above 285° and 100-200° (decomposition), resp.
There is still a lot of research devoted to this compound(SMILES：CC(Br)C(OCC)OCC)Synthetic Route of C7H15BrO2, and with the development of science, more effects of this compound(3400-55-3) can be discovered.
Reference:
Piperazine – Wikipedia,
Piperazines – an overview | ScienceDirect Topics