DOI: 10.1039/C5RA00406C
Page 7 of 9
Journal Name
RSC Advances
ARTICLE
and diisopropylethylamine (DIPEA) (8 mmol) in THF (25 mL) Centralized Instrumental Facility is gratefully acknowledged
for providing instrumental facilities.
2
under N atmosphere. The resulting slurry was stirred for a
period of 24 h and filtered. The residue thus obtained was
washed sequentially with 50 mL portions of methanol,
dichloromethane (DCM) and THF, and transferred to a RBF
containing piperazine (0.86 g, 10 mmol) in dry THF (25 mL)
Notes and references
a
Discipline of Inorganic Materials and Catalysis, CSIR- Central Salt and
Marine Chemicals Research Institute (CSIR-CSMCRI), G. B. Marg,
2
filtered and washed in the same manner as described above.
Finally the functionalized silica material was dried at RT under
vacuum for 6 h (Scheme 1) (1.1 g).
b
Academy of Scientific and Innovative Research, CSIR-Central Salt and
Marine Chemicals Research Institute (CSIR-CSMCRI), G. B. Marg,
Bhavnagar- 364 002, Gujarat, India
General method for aldol addition of ketones to isatins
Electronic Supplementary Information (ESI) available: [Materials and
To a 10 mL vial were added catalyst 25 mg, isatin 2a (50 mg, Methods, solid state NMR of catalyst and characterization data of final
.30 mmol) and acetone (1 mL). The resulting mixture was products including spectra, TEM images and N -adsorption-desorption
Information]. See
0
2
stirred at room temperature until the consumption of isatin, as isotherm are provided
monitored by TLC, occurred. The catalyst was separated using DOI: 10.1039/b000000x/
in
Supporting
centrifugation method and washed with acetone (5×2 mL). The
solution was then evaporated on rotavapor to get the crude aldol
product 3aa. The products were then purified by flash
chromatography using silica gel. The products thus obtained
were confirmed by the NMR with those with published
literature.
1
(a) Y. Q. Tang, I. Sattler, R. Thiericke, S. Grabley and X. Z. Feng,
Eur. J. Org. Chem., 2001, 261–267; (b) M. Toyota and M. Ihara,
Nat. Prod. Rep., 1998, 15, 327-340; (c) J. J. Song, J. T. Reeves, F.
Gallou, Z. Tan, N. K. Yee and C. H. Senanayake, Chem. Soc. Rev.,
2007, 36, 1120–1132; (d) R. J. Sundberg, The Chemistry of Indoles,
Academic, New York, 1970; (e) S. Lin, Z. Q. Yang, B. H. B. Kwok,
M. Koldobskiy, C. M. Crews and S. J. Danishefsky, J. Am. Chem.
Soc., 2004, 126, 6347-6355; (f) S. Lin and S. J. Danishefsky, Angew.
Chem., Int. Ed., 2002, 41, 512-515; (g) X. Z. Wearing and J. M.
General method for Knoevenagal condensation of isatins
To a 10 mL vial were added catalyst 20 mg, isatin 2a (50 mg,
0.30 mmol) and THF 2 mL as solvent. To the resulting mixture,
Cook, Org. Lett., 2002,
4 , 4237–4240.
(
1 equiv. 20 µL) of malononitrile was added. The red mixture
2
(a) G. W. Gribble, J. Chem. Soc. Perkin Trans., 2000, 1, 1045-1075;
thus obtained was stirred at room temperature until the
consumption of isatin, as monitored by TLC, occurred. The
catalyst was separated using centrifugation method and washed
with THF (5×2 mL). The solution was then evaporated on
rotavapor to get the crude knoevenagel products 4a. The
obtained crude products were of enough purity (>95%) but
further purification was done by flash chromatography using
silica gel. The products obtained were confirmed by NMR with
those reported in published literature.
(b) R. Dalpozzo, G. Bartolib and G. Bencivennib, Chem. Soc. Rev.,
2012, 41, 7247–7290; (c) N. Shibata, E. Suzuki, T. Asahi and M.
Shiro, J. Am. Chem. Soc., 2001, 123, 7001; (d) R. Shintani, M. Inoue
and T. Hayashi, Angew. Chem. Int. Ed., 2006, 45, 3353; (e) Z. Mao
and S. W. Baldwin, Org. Lett., 2004,
6, 2425–2428; (f) Z. Xiao, C.
Yu, T. Li, X. S. Wang, and C. Yao, Org. Lett., 2014, 16, 3632–3635;
(g) A. Singh, A. L. Loomer, and G. P. Roth, Org. Lett., 2012, 14
5266–5269.
,
3
(a) W. G. Sumpter and F. M. Miller, Chemistry of Heterocyclic
Compounds: Heterocyclic Compounds with Indole and Carbazole
General method for conjugate addition of acetone to
isatylidene malononitriles adducts
Systems, 2008,
S. Hibino, Nat. Prod. Rep., 2013, 30, 694–752; (c) A. Kumar and S.
S. Chimni, RSC Adv., 2012, , 9748–9762 (references therein).
(a) S. Mohammadi, R. Heiran, R. P. Herrera and E. M. López,
ChemCatChem., 2013, , 2131-2148; (b) N. Lashgari, and M.
8, 196-288; (b) M. Ishikura, T. Abe, T. Choshib and
To a 10 mL vial were added catalyst 75 mg, malononitrile
adduct 4a (58.5 mg, 0.30 mmol) and 1 mL acetone as
nucleophile and solvent. The resulting red mixture was stirred,
2
4
5
5
(
which changed to light brown) at room temperature until the
Ziarani, ARKIVOC, 2012, 277-320; (c) G. S. Singh and Z. Y. Desta,
Chem. Rev., 2012, 112, 6104−6155.
consumption of malononitrile adduct, as monitored by TLC,
occurred. The catalyst was separated using centrifugation
method and washed with Acetone (5×2 mL). The solution was
then evaporated on rotavapor to get the crude Isatylidene
malononitriles products 5a. The obtained crude products, which
solidified on standing, were purified by flash chromatography
using silica gel. The products obtained were confirmed by
NMR with those reported in published literature.
(a) A. Wurtz, Bull. Soc. Chim. Fr., 1872, 17, 436-442; (b) A. T.
Nielsen and W. J. Houlihan, The Aldol Condensation. Organic
Reactions, 2011, 16, 1–438; (c) B. M. Trost, Comprehensive Organic
Synthesis, Pergamon Press, Oxford, 1991,
Braude and H. G. Lindwall, J. Am. Chem. Soc., 1933, 55, 325–327;
e) S. J. Garden, R. B. da Silva, and A. C. Pinto, Tetrahedron., 2002,
, 8399
2, 133–340; (d) F.
(
5
8
Acknowledgements
The CSIR-CSMCRI registration no. is CSIR-CSMCRI-
6
(a) E. Knoevenagel, Chem. Ber., 1894, 27, 2345; (b) G. Jones, Org.
React. 1967, 15, 204; (c) D. V. Demchuk, M. N. Elinson and G. I.
Nikishin, Mendeleev Commun., 2011, 21, 224–225; (d) L. F. Tietze
and U. Beifuss, Comprehensive Organic Synthesis, Pergamon Press,
Oxford, 1991, 341; (e) N. Lashgaria, G. M. Ziarania, A. B. and P.
188/2014. Authors are thankful to CSIR-Indus Magic Project
CSC0123 for their financial support. Naveen Gupta is thankful
to AcSIR for Ph. D enrolment and DST for INSPIRE
fellowship under Doctoral Study. Analytical Discipline and
This journal is © The Royal Society of Chemistry 2012
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