ANTICOAGULANT REVERSAL AGENTS

1 . A compound of formula I

or a pharmaceutically acceptable salt thereof, wherein:

A is a linear diamine or a linear moiety containing a reactive functional group that can form a bond to X and X′, when present, or to Y and Y′, or a substituted piperazine ring where the substituted functional group is not a ketone, and wherein;

L and L′ are the same or different and are linkers;

X and X′ are the same or different and are absent or are a functional group that attaches the linker L to M and linker L′ to M′, respectively;

M and M′ are the same or different and are absent or is a linker that attaches X to Y and X′ to Y′, respectively; and

Y and Y′ are independently selected from

and —NH 2 .

2 . The compound of claim 1 , wherein the linear moiety or the substituted piperazine ring contain reactive functional groups that can form a bond to X and/or X′, when present, or Y and/or Y′.

3 . (canceled)

4 . The compound of claim 1 , wherein X and X′, when present, is a functional group that attaches linker L to Y and linker L′ to Y′, respectively, and wherein the functional group is selected from the group consisting of esters, amides, and ketones.

5 . The compound of claim 1 , wherein L and/or L′ is a substituted or unsubstituted alkylene chain that is C 1 to C 6 .

6 - 15 . (canceled)

16 . A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.

17 . The pharmaceutical composition of claim 16 , wherein the composition is adapted for enteral administration.

18 . The pharmaceutical composition of claim 17 , wherein the composition is adapted for oral administration.

19 . The pharmaceutical composition of claim 16 , wherein the composition is adapted for parenteral administration.

20 . The pharmaceutical composition of claim 19 , wherein the composition is adapted for intravenous or subcutaneous administration.

21 . A method of completely or partially reversing an anticoagulant effect of a coagulation inhibitor comprising administering to a subject in need thereof a therapeutically effective amount of a compound of claim 1 or pharmaceutically acceptable salt thereof.

22 - 35 . (canceled)

36 . A diagnostic kit comprising the compound of claim 1 .

37 . The kit of claim 36 , wherein the kit is used for determining an anticoagulant concentration in blood.

38 . A method of synthesis of diarginine piperazine, the method comprising the steps of;

a. In a first reaction, in the presence of a peptide coupling reagent, reacting at least about two equivalents of compound 1,

with one equivalent of compound 2,

thereby obtaining compound 3,

wherein P1 of compounds 1 and 3 is a protecting group and P2 of compounds 1 and 3 is a protecting group or is a hydrogen;

b. In a second reaction, removing all protecting groups from compound 3 in a deprotection reaction.

39 . The method of claim 38 , wherein the peptide coupling reagent is one of HBTU, EDC/HOBt, or an active OSu ester.

40 . The method of claim 39 , wherein the protecting group P1 is Boc, and the protecting group P2 is Pbf or hydrogen.

41 . The method of claim 39 , where the protecting group P1 is Boc and the protecting group P2 is hydrogen.

42 . The method of claim 38 , comprising the steps of;

a. In the first reaction, combining 2.2 equivalents of compound 1 with 1 equivalent of compound 2, wherein P1 of compound 1 is Boc and P2 of compound 1 is hydrogen, wherein the modified compound 1 is designated as Boc-Arg-OH·HCl, in the presence of a peptide coupling reagent, wherein the peptide coupling reagent is 2.6 equivalents EDC/2.6 equivalents HOBt, according to the reaction scheme

and,

b. In the second reaction, removing all protecting groups from compound 3 in a deprotection reaction, wherein the deprotecting reagent solution comprises 95% TFA/5% H 2 O, according to the reaction scheme