ENG 230 Final, Fall 2004

eet ce Chemistry 225 Final Examination Time: 2.5 hr. February 8. 1996 M.J.Haddadin 1. Give a reasonable mechanisin to explain the following transformation: o > © f a) We, Naot Cs => EmManol\ Nc As SACK, \) rteateg » FON) ie) (Ethanol) Nt b) CH Coa ory c-oGh, =A 2) WO sy 2) The infrared spectrum of compound A gives a carbonyl band at 1830 cm-l. The proton NMR spectrum consists of a broad singlet at § 7.34. The C'*NMR consists of four lines all in the § 100-200 region. The important ions in the mass spectrum are m = 63 (48%). 64 (100%). 92 € (56.2%), 136 (75.5%), 137 (6.19). Give the structure of compound A. 3. A Chemistry 225 student believed that one of his/her unknowns js compound A which reacted readily with Bro. further heating of the bromide product with hot KOH /ethnol yielded compound B which Spontaneously converted to C. a) Give the structures of B and C which contain no Br. b) Why do the two protons of the bridged methylene show at &- 0.5) in NMR spectrum of C? Be brief. c) Where do you expect the rest of the protons of C to appear in the NMR spectrum’ Give an estimated chemical shift. 4. a) Which otf the following compounds is water soluble and which is (are) not? Wo \ i) b) Which , if any, of the following compound's U.V. spectrum will be dramatically elfected by protonation and why? Be brief. go c)Consider the following reactions and give the structures of &D. \,5- Dibromopentane SY A tees ellos precipitabe hk Conc. Nady a BCG HN) \. cht Decolorizes Br2 (CClg, Dissolves in 5% HCI 2-A90, Declirizes Ba ‘CCly Dissolves in 5% HCl Does not react with HN’ Oy 5. A neutral compound (Cj gH] 3NO2) yields CgH] jNO upon warming with aqueous hydroxide. Heating CgH NO with HI gives CgH7NO which upon oxidation yields.p-benzoquinone. The NMR and IR of CyQH ,3NO92 are shown below. Give the structures of C} QH] 3NO2, CgH11NO and Wave number (cm 1 5000 3000 2000 1500 1300 110 f - @ 1000 90 7 100 [71 i rr ns 1 1 T i ” me =~ — Ces 80 ! - Ss a 2 60- = 40 “r 1 Le 1 ae ae 7 al a : 4 5 6 7 8 9 10 n 12 13 14 Wavelength (um | | ~ ra 5 ~ 3 _ = loes - sy TMS aL j — ~ iw Nba | i ® + [orate a” hee" beteneom - y wel ‘ 4 ‘uliaiatteel sada nae naeeta rao mand we Lio — A. 1 . lin os atte fate 1 8 7 6 5 4 3 ns rr Chemical shift (8) 6. Compound A (C1 9H 120) which, among other peaks in its proton NMR spectrum, has a singlet at 62.2 (3H). Upon heating at 200°c it was converted to a base soluble B (Cj Qf, 20). Heating of B with NaOH followed by aciditication gave C (C1QH 20). Treatment of B with a solution of aniline. sodium nitrite and HCl at 5°c and adjustment of the pli of the solution to 9. followed bv acidification gave a bright vellow product which upon reduction with Sn, HCI yielded D (C] 6H] gON2).Ozono ysis of B followed by reduction of the ozonide gave E (Co H}Q02). E reacted with ammoniacal silver nitrate to give, after acidification, F whic vielded G (Cg HgO9). F showed the same sing hot 5% NaOH. Give the structures of A-G, 1 upon heating with HCI let (3H) of A and dissolved in 7. A compound (A), containing only carbon, hydrogen , and oxygen, was found to react with acetyl chloride but not with phenylhydrazine. Oxidation with periodic acid converted it to a new compound (B), which reduced Tollens but not Fehling’s reagent. Treatment of B with potassium cyanide in aqueous ethanol converted it to a new compound (C). which gave positive tests with acetyl chloride and phenvlhydrazine. Oxidation of C with Fehling's solution or nitric acid converted it to a yellow compound (D) that vielded a derivative with o-phenylenediamine. When D was treated with hydrogen peroxide it yielded an acid () having a neutralization equivalent of 151-1. Catalytic hydrogenation of C or D produced the original compound (A). The nmy spectrum of compound B (in CDCI3) showed § 3.42. 3H, s; 6.9. 2H. d (J= 10 Hz); 7.56, 2H. d(J=10 Hz); 9.81, 1H. s. Give the structures of A-Br 9 %. A compound (1).giving positive tests for nitrogen and chlorine. was insoluble in water and hydrochloric acid but soluble in sodium bicarbonate solution. A neutralization equivalent of 210 + 2 was obtained. Compound I reacted with acetyl chloride but not with hot alcoholic silver nitrate. The acetyl derivative (II) had a neutralization equivalent of 253 - 2. Boiling alkali liberated ammonia from I, and acidification of the resulting solution precipitated a new acid (TIT), which had a neutralization equivalent of 115 | 1, Compound II contained chlorine but no nitrogen. When compound III was boiled with potassium permanganate solution, a new compound having the same solubility characteristics as I was produced that still contained chlorine and gave a neutralization equivalent of 81 + 1, Compound IV (neutralization equivalent 71 ) could be chlorinated to give the compound of neutralization equivalent 81. compound IV yielded an nmr spectrum (CDCI3, DMSO-d¢ solvent) displaving§ 7.57. 1 H.t (J - 7 Hz): 8.18, 2 H, d(J= 7 Hz), 11.2, 3 H, bs. The ir spectrum of I (in Nujol) showed, among other bands. strong absorptions at 1779 cm -! (5.62 m) and 1712 cm-! (5.84 m). Give the structures of ] - IV. TABLE 12.2 Carbon-13 NMR chemical shift correlations Type of carbon Chemical shift (8) Type of carbon Chemical shift (8) C—l 0-40 =C 100-150 C—Br 25-65 C—O 40-80 o cl 95 2n c=0 170-210 — CH, 110-160 —CH,— CH 100 Chemica! shift (44 Figure 12.6. Chemical shift correlations for C NMR.