Anthony Melvin Crasto presents Ladderanes Synthesis and overview

3.  A ladderane is an organic molecule containing two or
more fused rings of cyclobutane. The name is
a portmanteau because the serial cyclobutane rings look
like a ladder and are singly bonded like alkanes. The
chemical formula for a ladderane with n rings is C2n+2H2n+6.
The geometry of ladderanes is highly strained because
ligands to the carbon atoms cannot extend to their ideal
angles. However, examples of ladderanes have been
found in living organisms.[1] An example
ispentacycloanammoxic acid[2] which is composed of 5
fused cyclobutane units. It is found in bacteria performing
the anammox process where it forms part of a tight and
very dense membrane believed to prevent the organism
from losing the intermediate hydrazine which is involved in
the production of nitrogen and water from nitrite ions
and ammonia.[3]

4. A simple ladderane, consisting of three
fused cyclobutane rings

5.  Back in 2005, Corey and Mascitti prepared the
first enantioselective (single mirror image of a
compound) synthesis of
pentacycloanammoxic acid
(JACS 2006, 128,3118-3119). This C20 fatty acid,
firstdiscovered in deep-sea bacteria by Dutch
researchers in 2002, provides an extremely rigid
lipid bilayer to bacterial cell membranes,
which biologists believe shields them from their
own toxic metabolic byproducts – anammoxic
bacteria utilize ammonia for energy, and
produce hydrazine (rocket fuel) and
hydroxylamine as waste products en route to
N2 and H2O.

7. ^ a b Nouri, D H, Tantillo, D J (2006). "They Came from the Deep:
Syntheses, Applications, and Biology of Ladderanes". Curr. Org.
Chem. 10(16): 2055–2074. doi:10.2174/138527206778742678
.
^ J. S. Sinninghe Damsté, M. Strous, W. I. C. Rijpstra, E. C.
Hopmans, J. A. J. Geenevasen, A. C. T. van Duin, L. A. van Niftrik
and M. S. M. Jetten (2002). "Linearly concatenated cyclobutane
lipids form a dense bacterial membrane". Nature 419 (6908): 708–
712.doi:10.1038/nature01128. PMID 12384695.
^ Vincent Mascitti and E. J. Corey (2006). "Enantioselective
Synthesis of Pentacycloanammoxic Acid". J. Am. Chem.
Soc. 128 (10): 3118.doi:10.1021/ja058370g. PMID 16522072.

8.  Linearly concatenated cyclobutane
lipids form a dense bacterial membrane
 Jaap S. Sinninghe Damsté, Marc Strous,
W. Irene C. Rijpstra, Ellen C. Hopmans,
Jan A. J. Geenevasen, Adri C. T. van
Duin, Laura A. van Niftrik and Mike S. M.
Jetten
 Nature 419, 708-712(17 October 2002)
 doi:10.1038/nature01128

10. Enantioselective Synthesis of Pentacycloanammoxic Acid
Vincent Mascitti and E. J. Corey
pp 3118–3119
Publication Date (Web): February 16, 2006 (Communication)
DOI: 10.1021/ja058370g

27. "The synthesis of the 3- and 5-ladderanes is
a crowning achievement," says chemistry
professor Bruce M. Foxman of Brandeis
University. "The work provides both a new
subclass of solid-state photocycloaddition
products and an elegant example of how
the careful planning and execution of a
solid-state methodology may open the
door to a simple, high-yield synthesis of an
elusive class of molecules."

29.  A solid-state intermolecular synthesis of ladderanes that
provides gram amounts of these unusual compounds in
quantitative yields has been developed by assistant
chemistry professor Leonard R. MacGillivray and graduate
students Tomislav Frii and the late Xiuchun Gao of the
University of Iowa [Angew. Chem. Int. Ed.,43, 232 (2004)].
 Ladderanes feature a series of fused cyclobutane rings
that chemists believe could impart unique electronic
properties or serve as spacers to separate metals or
functional groups for a potential new class of
optoelectronic materials. Several groups have made short
ladderanes with limited success, building them up from
halogenated cyclobutenes, from alkenes and alkynes, or
by fusing together polyenes [Angew. Chem. Int.
Ed., 42, 2822 (2003)]. One problem, MacGillivray notes, is
that in solution the ladder precursors are probably too
disorganized to align and react properly.

30. Structures of ladderane lipids derived
from anammox bacteria and their
transformation products derived from
microbial oxic degradation. (1) C18-[5]-
ladderane FA, (2) C20-[5]-ladderane
FA, (3) C18-[3]-ladderane FA, (4) C20-[3]-
ladderane FA, (I) C14-[5]-ladderane FA,
(II) C14-[3]-ladderane FA, (III) C16-[3]-
ladderane FA. Key: FA = fatty acid.

45. 
 THANKS AND REGARD'S
DR ANTHONY MELVIN CRASTO Ph.Damcrasto@gmail.com
 MOBILE-+91 9323115463
 GLENMARK SCIENTIST , NAVIMUMBAI, INDIA
web link
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