DTIC ADA261496: The Development of New Protecting/Leaving Groups and Application to the Synthesis of Cage Nitramines

110 Pages·3.3 MB·English

by  Defense Technical Information Center

AD-A261 496
Final Technical Report- 5 January 1993
THE DEVELOPMENT OF NEW
PROTECTING/LEAVING GROUPS
AND APPLICATION TO THE
SYNTHESIS OF CAGE NITRAMINES
Prepared by:
Robert J. Schmitt, Department Director
Jeffrey C. Bottaro, Senior Chemist
Paul E. Penwell, Chemist
SRI International Project 6654
D T I
Prepared for:
CT
U.S. Office of Naval Research
Code 1132 E" 7 I
1 13
800 N. Quincy Street
Arlington, VA 22217 S
Q Attn: Dr. Richard Miller
Contract No. N00014-88-C-0537
Approved:
NNDavid S. R~irDossirector SLaboratory
.
I
(cid:127) Chemistry Laboratory
, David M. Golden
0')
~ Vice President
-~-
Physical Sciences Division (cid:127) d',. . , ,,.L
/31- 21 4
CONTENTS
LIST OF FIGURES ................................................................................... iv
INTRODUCTION ....................................................................................... I
SIGNIFICANT RESULTS DURING CONTRACT ............................................. 2
Condensation Reactions for Ring and Cage Synthesis ......................................... 2
Sulfamate Protecting Groups ................................................................... 2
Thiodipehnylphosphate Protecting Groups ................................................... 4
Attempts to Synthesize Isowurtzitanes by Reaction with Sulfamides ................... 7
Clathrates of CL-20 .................................................................................... 9
Dinitramide Salts ........................................................................................ 19
Cesium Dinitramide (SRI-1 1) ................................................................... 20
Ammonium Dinitramide (ADN, SRI-12) ..................................................... 25
Hydrazinium Dinitramide (SRI-13) ............................................................. 27
Hydroxylammonium Dinitramide and Hydroxylammonium-Hydroxylamine
Dinitramide (SRI-14) ......................................................................... 27
Guanidinium Dinitramide (SRI-21) ............................................................. 37
Cubane-1,4-bis(ammonitm dinitramnide)(SRI-17) ............................................ 38
Cubane- 1,2,4,7-tetrakis(ammonium dinitramide)(SRI- 19) .................................. 38
Acid and Base Stability of Dinitramide Salts ............................................... 46
EXPERIMENTAL ....................................................................................... 5'
Synthesis of Hyxahydro-1,3,5-tris(methanesulfonate)-1,3,5-triazine (J ...................... 51
Attempts to Convert (1) to RDX ................................................................... 51
Synthesis of N-(diphenylphosphine)-N,N-trimethylsilylamine (4) ............................. 51
Synthesis of N-(diphenylthiophosphate)-N,N-trimethylsilylamnine (5) ......................... 51
Synthesis of Hexahydro-tris(N,N',N"-diphenylthiophosphate)-1,3,5-triazine (fi) ........... 52
Synthesis of Glyoxal Tetraethylacetal (alternatively, 1,1,2,2,-Tetra-
(n-butylether)ethane) Compound (7_) ............................................................ 52
Synthesis of Meso-1,2-(n-butylether)-1,2-(N-trimethylsily-N-methanesulfonate)ethane (1) 52
Synthesis of (9) ........................................................................................ 52
Synthesis of Clathrate of CL-20 and HN (SRI-4) ............................................. 53
3
Synthesis of Clathrate of CL-20 and H 0 (SRI-5) ........................................... 53
2 2
Synthesis of Clathrate of CL-20 and NH OH (SRI-20) ....................................... 53
2
Synthesis of 1-(N,N-dinitramino)-2-trimethylsilylethane ........................................ 53
Synthesis ofCesium Dinitramide (SRI-I 1) ......................................................... 54
Synthesis of Tetramethylammonium Dinitramide ................................................. 54
Synthesis of Other Dinitramide Salts by Ion Exchange ........................................ 54
REFERENCES .......................................................................................... 55
ii
ACKNOW LEDGEM ENTS ............................................................................ 56
APPENDICES
A SYNTHESIS OF ENERGETIC CLATHRATES ................................... A-1
B DINITRAMIDE SALTS AND METHOD OF MAKING SAME
(INTERNATIONAL PATENT APPLICATION NO. WO 91/19669) ........... B-I
C A NEW SYNTHESIS OF ALKYL-N,N-DINITRAMINES BY DIRECT
NITRATION OF ISOCYANATES ................................................... C-1
AcoeSsiOn For
Ur'', .- spcd cl
]WIGIC QTA-EJUTyil I.T..
LIST OF FIGURES
I Partial crystal structure of hexahydro-tris(NN',N"-diphenylthio(phosphate)-
1,3,5-triazene (Compound 6) .................................................................... 5
2 Crystal structure of hexahydro-tris(N,NXN"-diphenylthiophosphate)-1,3,5-
triazene (Compound 6) ......................................................................... 6
3 Crystal structure of meso-1,2-bis(N,N'-trimethylsilyl-NN'-methyl-sulfonate)-
1,2-bis(N'-butoxyl)ethane ...................................................................... 8
4 Crystal strcture of SRI-4 ........................................................................ 12
5 Crystal structure of SRI-4 ........................................................................ 13
6 Crystal structure of SRI-5 showing oxygen closest approaches to CI-20 .................. 14
7 TGA of SRI-5 showing H 0 loss ............................................................. 15
2 2
8 Crystal structure of SRI-8 showing N and 0 positions for hydroxylamine ................ 17
9 DSC of SRI-20 .................................................................................... 18
10 Crystal structure of CsN(NO2)2 (SRI-11) ..................................................... 22
11 DSC of CsN(NO2)2 (SRI-11) ................................................................... 24
12 Crystal structure of ammonium dinitramide (SRI-12) ........................................ 28
13 Partial crystal lattice view showing closest approach of 4 dinitramide anions to
the ammonium ion ................................................................................. 29
14 Partial crystal lattice view showing closest approach of 4-ammonium ions to one
dinitramide anion .................................................................................. 30
15 View of dinitramide ion down the plane of the ion ........................................... 31
16 DSC of ammonium dinitramide .................................................................. 32
17 TGA of ammonium dinitramide ................................................................. 33
18 Crystal structure of hydrazinium dinitramide (SRI-13) ....................................... 34
19 DSC of hydrazinium dinitramide (SRI-13) ..................................................... 35
20 Crystal structure of SRI-14 ...................................................................... 36
iv
21 Crystal structure of guanidinium dinitramide (SRI-21) showing 2 molecules in view .... 39
22 View of crystal lattice of guanidinium dinitramide ........................................... 40
23 DSC of guanidinium dinitramide ................................................................ 41
24 Crystal structure of cubane-l,4-bis(ammonium dinitramide) ................................ 42
25 DSC of cubane-1,4-bis(ammonium dinitramide) .............................................. 43
26 Crystal structure of cubane-1,2,4,7-tetrakis(ammonium dinitramide) ...................... 44
27 View of crystal lattice of cubane- 1,2,4,7-tetrakis(ammonium dinitramide) ................ 45
28 DSC of cubane-1,2,4,--tetrakis(ammonium dinitramide) .................................... 47
V
INTRODUCTION
This final report details the results accomplished on Office of Naval Research
(ONR) Contract No. N00014-88-C-0537 (SRI Project No. 6654). In the course of this
study, we have accomplished the synthesis of a new, stable class of dinitramide salts that
will have both fundamental scientific interest and practical applications. We have also
developed a new type of condensation reaction for the synthesis of cage compounds and
prepared new clathrates of CL-20 with significantly more energy than pure CL-20. The
dinitramide salts are based on a newly discovered inorganic anion known as the dinitranide
anion, N(NO )2. The dinitramide anion is a uniquely stable, high oxygen density grouping
2
that can be prepared in many different combinations, including the ammonium salts (SRI-
12).
SIGNIFICANT RESULTS DURING CONTRACT
The results of these studies on the synthesis of energetic materials fall into three
categories: (1) condensation reactions for ring and cage synthesis, (2) Clathrates of CL-20,
and (3) synthesis of SRI-12.
CONDENSATION REACTIONS FOR RING AND CAGE SYNTHESIS
Sulfamate Protecting Groups
Development of improved methods for synthesizing of the CL-20 cage is of
primary importance because of the need for new and simplified routes to CL-20. We
investigated methodology based on using the phosphoramide or sulfamide moieties to build
the scaffold required for the construction of cage molecules in this project. We previously
observed that phosphoramide and sulfamide groups are effective as protecting groups in
synthesis reactions and are good leaving groups in nitration reactions. Some progress has
been made in this area through the synthesis of important preliminary compounds. Further
research should lead to the synthesis of CL-20.
Our preliminary studies have shown phosphoramides to be excessively
hydrolytically labile. To address this problem, we have investigated the reactions of
anhydrous versions of glyoxal and formaldehyde with phosphoramides and sulfamides.
From these preliminary results, we focused our attempts at cage synthesis on the reaction
of mono- and bifunctional sulfonamides with formaldehyde and glyoxal. This strategy has
not yet led to self-assembling molecules that provide us easy access to cage structures, but
it still holds great promise. These studies have resulted in the synthesis of phosphoramide
and sulfamide precursors to RDX, and we have undertaken the initial steps toward a CL-20
cage structure.
N,N-Bis-trimethylsilylmethanesulfonamide condensed cleanly with
dimethoxymethane in the presence of Me Si-OTf catalyst to give the triazine I (see Scheme
3
1), which, surprisingly, could not be nitrated by nitronium tetrafluoroborate to give RDX.
N, N-Bis-trimethylsilylmethanesulfonamide was also condensed with
trimethylorthoformate to give compound 2. as shown in Scheme 1. Further attempts to
2
SO2CH3
CH2(OCH3)2
MeSO2N(TMS)2 Catalytic
Me SiOS° CF CH 02S,,,-v',N,,SO CH
3 2 3 3 2 3
HHC(3O) 3HC(OCH3)3
N2
OO-. . 3 NO
Catalytic- (cid:127) C atalytic . 2
o H A e 2C "F N RD/
CH--N=( -
o OCH MeSO N(TMS) X-N-N (cid:127) -X
0 3 2 2
a.
X = CH SO
3 2
(1)
Scheme 1. Reaction of N,N-bis-trimethylsilylmethanesulfonamide with
protected aldehydes and acids
condense more N,N-bis-trimethylsilylmethanesulfonamide failed to give the desired
product 3. Direct reaction of NN-bis-trimethylsilylmethanesulfonamide with
trimethylorthoformate and catalytic quantities of Me Si-OTf also failed to give 3 directly.
3
We believe that this reaction failed because the thermodynamic cost of rehybridizating the
formyl carbon atom of 2 from sp2 to sp3 (as is the case in 3) is prohibitive, because
electrons have been donated from the esteric oxygen of 2 to the sulfonated nitrogen. The
failure to rehybridize prevents the formation of 3 by oligomerization of 2 and NN-bis-
trimethylsilylmethanesulfonamide.
All attempts to convert compound 1 to RDX by reaction with NO BF or in mixed
2 4
sulfuric/nitric acids gave either unreacted starting material or, if the reaction was heated no
product at all. Available evidence indicates that compound 1 is more stable to acid than
RDX.
3
Thiodiphenylphosphate Protecting Groups
The second route that we attempted was to use thiodiphenylphosphoryl groups as
the protecting/leaving groups for the synthesis of ring and cage compounds. The reaction
sequence followed is shown in Scheme 2. In this reaction sequence, diphenyl
chlorophosphine is reacted with lithium bis-NN-trimethylsilylamide to give compound 4.
The phosphine derivative of compound A is converted to the thiophosphoramide by
reaction with S and heat to give compound I which is then condensed cleanly with
8
dimethylacetal and catalytic quantities of Me Si-OTf to give compound A. Two views of
3
the crystal structure of compound A are shown in Figures 1 and 2.*
All attempts to convert compound A to RDX by nitration with nitric acid/nitronium
tetrafluoroborate proved unsuccessful. We believe that this nitration reaction failed because
of hydrolysis of the C-N bonds of tl- triazine occurring faster than nitration hence resulting
in degradation of the ring system.
C H \ LiN(Si(CH ) ) C H \ Si(CH )
6 5 3 3 2 6 5 3 3
P--Cl P--N
C 1H C HI Si(CH )
6 6 3 3
SII SA
C H -P--C H
6 5 6 5
S si(H)
CA~ -Is CH2(OCH3)2 C6H5m-1- --N i(CH3)3
l(cid:127)o\/N (cid:127)/N,,,P6 Catalytic P
(CHN)TSiOCfI \Si(CH )
S I / ""s 3)3SiOTH C 5 3 3
C615- C61-5 C11
SHN03
NO2BF4
No Reaction
to RDX
Scheme 2: Synthesis of Hexahydro-tris(N,N',N"-diphenylthiophosphate)-1,3,5-triazine
* All crystal structures in this project were determined by R. Gilardi, J. Flippen-Anderson, and C. George at
the Laboratory for the Structure of Matter at the Naval Research Laboratory (NRL). The authors
gratefully acknowledge their contributions.
4
F.iueP rta cytl tutueofhxhyr-ti(,N,"dihnyti~popht) 135
t(roiamzpnoeu d 61
NI5