J Chem Crystallogr (2011) 41:1386–1390
1387
Fig. 1 Molecular scheme
of N-methyl-N-(1-
phenylvinyl)benzamide (I)
CH3
N
O
I
ethanol was added dropwise via a syringe. 15 g KOH
(0.26 mol) pellets were added and the mixture was stirred
at room temperature for 4 h. The reaction mixture was
filtered and the filtrate was extracted with ether. The ether
extract was washed three times. The organic layer was
dried over sodium sulphate and concentrated in vacuum to
give an oil. The oil was distilled to give 24.5 g of a mixture
of acetophenone and imine. 1 g of mixture contains
Fig. 2 X-ray structure of N-methyl-N-(1-phenylvinyl)benzamide
Photolysis and Quantum Yield Result
1
1.17 mmol of imine (Int) by H NMR spectroscopy. The
spectral data for imine (Int) in the mixture: 1H NMR
At lower concentrations the Compound (I) has kmax below
˚
3,000 A. The compound was thus photolysed without a
(CDCl3) d 2.14 (s, 3H), 3.28 (s, 3H), 7.2–7.9 (m, 5H).
Pyrex filter. From 1H NMR spectroscopy, it was found that
two products were formed as a result of the photochemical
reaction as shown in Eq. 2.
Synthesis of N-Methyl-N-(1-Phenylvinyl)Benzamide (I)
15 g of distilled mixture contains 1.5 g (11.2 mmol) was
taken in a round bottom flask. Then 15 mL of triethyl
amine was added to it. 1.7 g of benzoyl chloride in 15 mL
of benzene was added at 5–8 °C. The reaction mixture was
warmed to room temperature, and refluxed for 4 h. Upon
cooling, triethylamine hydrochloride salt was filtered. The
filtrate was concentrated in vacuo and the residue was
dissolved in benzene. The benzene solution was washed
with NaHCO3, brine, dried over Na2SO4, and concentrated
in vacuo. The residue was chromatographed on silica gel,
eluting with 33% ethyl acetate in hexane to obtain 2.34 g
(89% yield) of enamide (I). The colorless block shaped
crystalline enamide (I) was obtained after crystallization
from 25% ethyl acetate in hexane. The spectral data were
CH3
CH3
N
CH3
N
N
O
O
O
hv
H
H
+
H
H
I
B
A
ð2Þ
Photolysis of I in 50% H2O in CH3CN gave lactam A as
major product and lactam B as minor product. The lactam
1
A and B were characterized by H and 13C NMR Spec-
troscopy. It is experimentally found that the quantum yield
for formation of lactam A in 50% aqueous CH3CN is 0.023
˚
at 2800 A. The proposed mechanism for formation of
1
lactam A and B are given in Schemes 1 and 2.
as follows: H NMR (CDCl3) d 3.23 (s, 3H), 4.84 (s, 1H),
5.34 (s, 1H), 7.1–7.6 (m, 10H); 13C NMR (CDCl3) d 36.62,
112.74, 126.40, 127.93, 128.05, 129.10, 129.20, 130.15,
136.15, 136.33, 149.42, 171.94.
Results and Discussion
The title compound C16H15NO, consists of a phenylvinyl
group in conjugation with N-methyl substituted benzamide
moiety. The crystal data and structure refinement details
are provided in Table 1. The selected Bond lengths, bond
and torsion angles are reported in Table 2. The bond length
of vinyl group C(7)–C(8) in compound (I) is found to be
Crystal Structure of Title Compound (I)
The crystal structure of Compound (I) was obtained from
modern X-ray diffractometer (Brucker-APEX2) with CCD
˚
camera and Cu–Ka (k = 1.54178 A) at 100(2) K. The data
collection for structure I was carried out by APEX2 v2.1–4
(Bruker, 2007). The cell refinement and structure refine-
ment was carried out by SAINT v7.23A (Bruker, 2005) and
SHELXL-97 v. 97-2 (Sheldrick, 1993–1997), respectively.
In Fig. 2, the X-ray structure of enamide (I) is shown with
atomic lebelling.
˚
1.3327(16) A that is very close to the theoretical value for
a double bond. Compound I can be cyclized at either of
two equivalent ortho positions i.e. at C(12) and C(16). The
bond distances from the vinyl group to its ortho positions
˚
are 3.58 and 4.03 A. The closure distance might be the path
123
Dehury, Sujit Kumar
